/* ============================================================
   水木硅谷 · 具身智能教育官网
   Blueprint Lab — 工程蓝图 × 编辑排版
   ============================================================ */

:root {
  --paper: #f6f3ec;
  --paper-2: #efeade;
  --paper-3: #e7e1d2;
  --ink: #16211d;
  --ink-soft: #46534c;
  --ink-faint: #7c867f;
  --accent: #e4552d;
  --accent-deep: #c23a16;
  --accent-2: #0f7b6c;
  --accent-2-deep: #0a5d52;
  --line: #d9d2c2;
  --line-strong: #b9b0a0;
  --white: #fffdf8;
  --grid: rgba(22, 33, 29, 0.055);
  --grid-strong: rgba(22, 33, 29, 0.09);
  --shadow-1: 0 2px 10px rgba(22, 33, 29, 0.08);
  --shadow-2: 0 14px 40px rgba(22, 33, 29, 0.14);
  --radius: 6px;
  --font-serif: "Noto Serif SC", "Source Han Serif SC", "Songti SC", "STSong", "SimSun", serif;
  --font-sans: "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", "WenQuanYi Micro Hei", "Helvetica Neue", sans-serif;
  --font-mono: "JetBrains Mono", "Cascadia Code", "SFMono-Regular", Consolas, "Courier New", monospace;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-sans);
  background: var(--paper);
  color: var(--ink);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button { font-family: inherit; cursor: pointer; }
ul { list-style: none; }

::selection { background: var(--accent); color: var(--white); }

/* ---------- 背景蓝图网格 ---------- */
.blueprint {
  background-image:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 44px 44px;
}

/* ---------- 排版工具 ---------- */
.serif { font-family: var(--font-serif); }
.mono { font-family: var(--font-mono); }

.tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent-2);
}
.tag::before {
  content: "";
  width: 26px; height: 1px;
  background: currentColor;
  display: inline-block;
}

.section { padding: 96px 0; position: relative; }
.section--tight { padding: 72px 0; }
.section--dark {
  background: var(--ink);
  color: var(--paper);
}
.section--dark .tag { color: #5ec4b2; }

.wrap { max-width: 1200px; margin: 0 auto; padding: 0 28px; }

.section-head { margin-bottom: 56px; max-width: 720px; }
.section-head--center { margin-left: auto; margin-right: auto; text-align: center; }
.section-head--center .tag { justify-content: center; }

h1, h2, h3 { font-family: var(--font-serif); font-weight: 700; line-height: 1.28; }

.h-title {
  font-size: clamp(30px, 4.4vw, 48px);
  margin-top: 14px;
  letter-spacing: 0.02em;
}
.h-sub {
  margin-top: 18px;
  color: var(--ink-soft);
  font-size: 16px;
}

.section--dark .h-sub { color: #b9c6c0; }

/* ---------- 顶部技术条 ---------- */
.topbar {
  background: var(--ink);
  color: #9fb0a8;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  padding: 7px 0;
}
.topbar .wrap {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}
.topbar b { color: var(--paper); font-weight: 500; }

/* ---------- 导航 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(246, 243, 236, 0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}
.brand { display: flex; align-items: center; gap: 12px; }
.brand-mark {
  width: 40px; height: 40px;
  flex: none;
}
.brand-name {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 20px;
  letter-spacing: 0.06em;
  line-height: 1.15;
}
.brand-name small {
  display: block;
  font-family: var(--font-mono);
  font-size: 9px;
  letter-spacing: 0.3em;
  color: var(--ink-faint);
  font-weight: 400;
}
.nav-links { display: flex; align-items: center; gap: 6px; }
.nav-links a {
  font-size: 15px;
  padding: 8px 16px;
  border-radius: var(--radius);
  color: var(--ink-soft);
  position: relative;
  transition: color 0.2s, background 0.2s;
}
.nav-links a:hover { color: var(--ink); background: var(--paper-2); }
.nav-links a.active { color: var(--accent-deep); font-weight: 600; }
.nav-links a.active::after {
  content: "";
  position: absolute;
  left: 16px; right: 16px; bottom: 2px;
  height: 2px;
  background: var(--accent);
}

.nav-actions { display: flex; align-items: center; gap: 10px; }

.cart-btn {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  border: 1px solid var(--line-strong);
  background: var(--white);
  color: var(--ink);
  padding: 9px 16px;
  border-radius: var(--radius);
  font-size: 14px;
  transition: all 0.2s;
}
.cart-btn:hover { border-color: var(--accent); color: var(--accent-deep); }
.cart-count {
  position: absolute;
  top: -7px; right: -7px;
  min-width: 19px; height: 19px;
  padding: 0 5px;
  border-radius: 10px;
  background: var(--accent);
  color: #fff;
  font-family: var(--font-mono);
  font-size: 11px;
  line-height: 19px;
  text-align: center;
  display: none;
}
.cart-count.show { display: inline-block; animation: pop 0.3s ease; }
@keyframes pop { 50% { transform: scale(1.35); } }

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  width: 42px; height: 42px;
  position: relative;
}
.nav-toggle span, .nav-toggle::before, .nav-toggle::after {
  content: "";
  position: absolute;
  left: 10px; right: 10px;
  height: 2px;
  background: var(--ink);
  transition: 0.25s;
}
.nav-toggle span { top: 20px; }
.nav-toggle::before { top: 12px; }
.nav-toggle::after { top: 28px; }
.nav-toggle.open span { opacity: 0; }
.nav-toggle.open::before { top: 20px; transform: rotate(45deg); }
.nav-toggle.open::after { top: 20px; transform: rotate(-45deg); }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 13px 26px;
  border-radius: var(--radius);
  font-size: 15px;
  font-weight: 600;
  border: 1px solid transparent;
  transition: all 0.22s;
  white-space: nowrap;
}
.btn .arr { transition: transform 0.22s; }
.btn:hover .arr { transform: translateX(4px); }
.btn--accent { background: var(--accent); color: #fff; }
.btn--accent:hover { background: var(--accent-deep); box-shadow: 0 8px 22px rgba(228, 85, 45, 0.35); }
.btn--ghost { border-color: var(--line-strong); color: var(--ink); background: transparent; }
.btn--ghost:hover { border-color: var(--ink); background: var(--white); }
.btn--dark { background: var(--ink); color: var(--paper); }
.btn--dark:hover { background: #24332d; }
.btn--light { background: var(--paper); color: var(--ink); }
.btn--light:hover { background: #fff; }
.btn--sm { padding: 9px 16px; font-size: 13px; }

/* ---------- Hero ---------- */
.hero {
  position: relative;
  padding: 88px 0 72px;
  border-bottom: 1px solid var(--line);
  overflow: hidden;
}
.hero::after {
  content: "";
  position: absolute;
  right: -160px; top: -160px;
  width: 560px; height: 560px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(228, 85, 45, 0.14), transparent 65%);
  pointer-events: none;
}
.hero-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 56px;
  align-items: center;
}
.hero-kicker {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.18em;
  color: var(--accent-2);
  text-transform: uppercase;
  display: flex;
  align-items: center;
  gap: 10px;
}
.hero-kicker::before { content: "▚▚"; color: var(--accent); font-size: 11px; }
.hero h1 {
  font-size: clamp(38px, 5.6vw, 66px);
  margin: 22px 0 10px;
  letter-spacing: 0.03em;
}
.hero h1 .hl {
  color: var(--accent);
  position: relative;
  white-space: nowrap;
}
.hero h1 .hl::after {
  content: "";
  position: absolute;
  left: 0; right: 0; bottom: 6px;
  height: 10px;
  background: rgba(228, 85, 45, 0.16);
  z-index: -1;
}
.hero-lead {
  font-size: 17px;
  color: var(--ink-soft);
  max-width: 540px;
  margin: 18px 0 30px;
}
.hero-ctas { display: flex; gap: 14px; flex-wrap: wrap; margin-bottom: 40px; }

.hero-stats {
  display: flex;
  gap: 0;
  border: 1px solid var(--line);
  background: rgba(255, 253, 248, 0.7);
  border-radius: var(--radius);
  overflow: hidden;
  max-width: 560px;
}
.hero-stats .stat {
  flex: 1;
  padding: 18px 20px;
  border-right: 1px solid var(--line);
}
.hero-stats .stat:last-child { border-right: none; }
.stat b {
  font-family: var(--font-serif);
  font-size: 28px;
  color: var(--accent-deep);
  display: block;
  line-height: 1.2;
}
.stat span { font-size: 12.5px; color: var(--ink-faint); }

.hero-art {
  position: relative;
  display: flex;
  justify-content: center;
}
.hero-art .robot-wrap {
  width: min(420px, 100%);
  animation: floaty 6s ease-in-out infinite;
}
@keyframes floaty { 50% { transform: translateY(-14px); } }

.hero-art::before {
  content: "";
  position: absolute;
  inset: 8% 4% 0;
  background: linear-gradient(160deg, rgba(15, 123, 108, 0.12), rgba(228, 85, 45, 0.12));
  border-radius: 50%;
  filter: blur(30px);
}

.spec-note {
  position: absolute;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--ink-faint);
  background: var(--white);
  border: 1px dashed var(--line-strong);
  padding: 6px 12px;
  border-radius: 3px;
  animation: floaty 7s ease-in-out infinite;
}
.spec-note--1 { top: 6%; left: 0; }
.spec-note--2 { bottom: 10%; right: 2%; animation-delay: 1.2s; }

/* ---------- 业务矩阵 ---------- */
.biz-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}
.biz-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 30px 26px;
  position: relative;
  transition: transform 0.25s, box-shadow 0.25s, border-color 0.25s;
}
.biz-card::before {
  content: "";
  position: absolute;
  top: 10px; left: 10px; right: 10px; bottom: 10px;
  border: 1px solid transparent;
  border-radius: 4px;
  pointer-events: none;
  transition: border-color 0.25s;
}
.biz-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-2); border-color: var(--line-strong); }
.biz-card:hover::before { border-color: rgba(228, 85, 45, 0.4); }
.biz-num {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--accent);
  letter-spacing: 0.2em;
}
.biz-icon { width: 54px; height: 54px; margin: 18px 0 14px; }
.biz-card h3 { font-size: 19px; margin-bottom: 10px; }
.biz-card p { font-size: 14px; color: var(--ink-soft); }

/* ---------- 特色区 (index 双栏) ---------- */
.split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}
.split .frame-art { position: relative; }
.frame-art .frame-inner {
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: var(--white);
  padding: 18px;
  position: relative;
}
.frame-art .corner { position: absolute; width: 18px; height: 18px; border: 2px solid var(--accent); }
.frame-art .corner--tl { top: -2px; left: -2px; border-right: none; border-bottom: none; }
.frame-art .corner--tr { top: -2px; right: -2px; border-left: none; border-bottom: none; }
.frame-art .corner--bl { bottom: -2px; left: -2px; border-right: none; border-top: none; }
.frame-art .corner--br { bottom: -2px; right: -2px; border-left: none; border-top: none; }

.check-list { margin-top: 26px; }
.check-list li {
  display: flex;
  gap: 14px;
  padding: 13px 0;
  border-bottom: 1px dashed var(--line);
  align-items: baseline;
  font-size: 15px;
}
.check-list li:last-child { border-bottom: none; }
.check-list .ck {
  color: var(--accent-2);
  font-family: var(--font-mono);
  font-weight: 700;
  flex: none;
}

/* ---------- 课程卡片 ---------- */
.course-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.course-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: transform 0.25s, box-shadow 0.25s;
}
.course-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-2); }
.course-top {
  padding: 24px 24px 18px;
  border-bottom: 1px dashed var(--line);
  position: relative;
  background:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 26px 26px;
}
.course-top .lvl {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--accent);
}
.course-top h3 { font-size: 20px; margin-top: 8px; }
.course-top .who {
  font-size: 13px;
  color: var(--ink-faint);
  margin-top: 6px;
}
.course-body { padding: 20px 24px 24px; flex: 1; display: flex; flex-direction: column; }
.course-body ul { margin-bottom: 18px; }
.course-body li {
  font-size: 13.5px;
  color: var(--ink-soft);
  padding: 5px 0;
  display: flex;
  gap: 10px;
}
.course-body li::before { content: "▸"; color: var(--accent-2); flex: none; }
.course-foot {
  margin-top: auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-top: 1px dashed var(--line);
  padding-top: 16px;
}
.course-price { font-family: var(--font-mono); font-size: 12px; color: var(--ink-faint); }
.course-price b { font-size: 17px; color: var(--accent-deep); font-weight: 700; }

/* ---------- 产品卡片 ---------- */
.product-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.product-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: transform 0.25s, box-shadow 0.25s;
  position: relative;
}
.product-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-2); }
.product-card.hot::after {
  content: "热销";
  position: absolute;
  top: 14px; right: 14px;
  background: var(--accent);
  color: #fff;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  padding: 4px 10px;
  border-radius: 3px;
  z-index: 2;
}
.product-media {
  background:
    radial-gradient(circle at 70% 20%, rgba(15, 123, 108, 0.1), transparent 55%),
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px),
    var(--paper-2);
  background-size: auto, 30px 30px, 30px 30px, auto;
  padding: 30px;
  aspect-ratio: 1 / 1;
  display: flex;
  align-items: center;
  justify-content: center;
}
.product-media svg { width: 82%; height: 82%; transition: transform 0.4s ease; }
.product-media img.product-photo { width: 100%; height: 100%; object-fit: cover; border-radius: 4px; transition: transform 0.4s ease; }
.product-card:hover .product-media img.product-photo { transform: scale(1.05); }
.product-card:hover .product-media svg { transform: scale(1.07) rotate(-1.5deg); }
.product-info { padding: 22px 24px 24px; display: flex; flex-direction: column; flex: 1; }
.product-code {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--ink-faint);
}
.product-info h3 { font-size: 19px; margin: 6px 0 8px; }
.product-desc { font-size: 13.5px; color: var(--ink-soft); flex: 1; }
.product-meta {
  display: flex;
  gap: 14px;
  margin: 14px 0 16px;
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--accent-2);
}
.product-meta span { display: inline-flex; align-items: center; gap: 5px; }
.product-buy {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  border-top: 1px dashed var(--line);
  padding-top: 16px;
}
.price { font-family: var(--font-mono); }
.price .cur { font-size: 13px; color: var(--ink-faint); }
.price b { font-size: 24px; color: var(--accent-deep); font-weight: 700; }
.price .orig { font-size: 12px; color: var(--ink-faint); text-decoration: line-through; margin-left: 6px; }
.buy-btns { display: flex; gap: 8px; }

/* ---------- 数据带 ---------- */
.data-band {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  border: 1px solid rgba(255, 253, 248, 0.16);
  border-radius: var(--radius);
  overflow: hidden;
}
.data-band .cell {
  padding: 34px 28px;
  border-right: 1px solid rgba(255, 253, 248, 0.14);
  text-align: center;
}
.data-band .cell:last-child { border-right: none; }
.data-band .num {
  font-family: var(--font-serif);
  font-size: 40px;
  color: #5ec4b2;
  line-height: 1.1;
}
.data-band .num sup { font-size: 20px; }
.data-band .lbl { font-size: 13px; color: #9fb0a8; margin-top: 6px; letter-spacing: 0.08em; }

/* ---------- 流程步骤 ---------- */
.steps { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; counter-reset: step; }
.step {
  position: relative;
  border: 1px dashed var(--line-strong);
  border-radius: var(--radius);
  padding: 30px 24px;
  background: rgba(255, 253, 248, 0.6);
}
.step::before {
  counter-increment: step;
  content: "0" counter(step);
  font-family: var(--font-mono);
  font-size: 30px;
  color: var(--accent);
  font-weight: 700;
  display: block;
  margin-bottom: 12px;
}
.step h3 { font-size: 17px; margin-bottom: 8px; }
.step p { font-size: 13.5px; color: var(--ink-soft); }

/* ---------- CTA 条 ---------- */
.cta-band {
  position: relative;
  overflow: hidden;
  padding: 72px 0;
  text-align: center;
}
.cta-band::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    linear-gradient(var(--grid-strong) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-strong) 1px, transparent 1px);
  background-size: 40px 40px;
  opacity: 0.5;
  pointer-events: none;
}
.cta-band .wrap { position: relative; }
.cta-band h2 {
  font-size: clamp(28px, 4vw, 44px);
  margin-bottom: 14px;
}
.cta-band p { color: var(--ink-soft); max-width: 620px; margin: 0 auto 32px; }
.cta-band .ctas { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }

/* ---------- 时间线 ---------- */
.timeline { position: relative; padding-left: 34px; }
.timeline::before {
  content: "";
  position: absolute;
  left: 8px; top: 6px; bottom: 6px;
  width: 2px;
  background: linear-gradient(var(--line-strong), var(--accent));
}
.tl-item { position: relative; padding: 0 0 40px 10px; }
.tl-item::before {
  content: "";
  position: absolute;
  left: -31px; top: 8px;
  width: 12px; height: 12px;
  border-radius: 50%;
  background: var(--paper);
  border: 3px solid var(--accent);
}
.tl-item .yr { font-family: var(--font-mono); font-size: 13px; color: var(--accent-2); letter-spacing: 0.12em; }
.tl-item h3 { font-size: 18px; margin: 4px 0 6px; }
.tl-item p { font-size: 14px; color: var(--ink-soft); max-width: 640px; }

/* ---------- 页脚 ---------- */
.site-footer {
  background: var(--ink);
  color: #aebcb5;
  padding: 64px 0 0;
  font-size: 14px;
}
.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1.2fr;
  gap: 40px;
  padding-bottom: 48px;
}
.footer-grid h4 {
  color: var(--paper);
  font-size: 15px;
  margin-bottom: 16px;
  letter-spacing: 0.06em;
}
.footer-grid a { display: block; padding: 5px 0; transition: color 0.2s; }
.footer-grid a:hover { color: var(--accent); }
.footer-about p { margin-top: 14px; font-size: 13.5px; max-width: 300px; color: #8fa098; }
.footer-contact li { display: flex; gap: 10px; padding: 6px 0; align-items: baseline; }
.footer-contact .k { font-family: var(--font-mono); font-size: 11px; color: #5ec4b2; flex: none; }
.footer-bottom {
  border-top: 1px solid rgba(255, 253, 248, 0.12);
  padding: 18px 0;
  display: flex;
  justify-content: space-between;
  gap: 10px;
  flex-wrap: wrap;
  font-family: var(--font-mono);
  font-size: 11.5px;
  color: #77877f;
  letter-spacing: 0.06em;
}

/* ---------- 页头横幅 (内页) ---------- */
.page-hero {
  position: relative;
  padding: 64px 0 56px;
  border-bottom: 1px solid var(--line);
  background:
    radial-gradient(circle at 85% 20%, rgba(228, 85, 45, 0.1), transparent 50%),
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: auto, 40px 40px, 40px 40px;
}
.page-hero h1 { font-size: clamp(30px, 4.4vw, 46px); margin-top: 12px; }
.page-hero .crumb {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--ink-faint);
  letter-spacing: 0.14em;
  margin-top: 14px;
}
.page-hero .crumb b { color: var(--accent-deep); font-weight: 500; }

/* ---------- 课程详情表 ---------- */
.detail-table { width: 100%; border-collapse: collapse; font-size: 14.5px; }
.detail-table th, .detail-table td {
  text-align: left;
  padding: 15px 18px;
  border: 1px solid var(--line);
}
.detail-table th {
  background: var(--paper-2);
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.1em;
  color: var(--ink-soft);
  font-weight: 600;
  width: 150px;
}
.detail-table tr:nth-child(even) td { background: rgba(255, 253, 248, 0.5); }

/* ---------- 信息卡 ---------- */
.info-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.info-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 28px 26px;
  transition: transform 0.25s, box-shadow 0.25s;
}
.info-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-2); }
.info-card .ic { font-size: 30px; }
.info-card h3 { font-size: 17px; margin: 12px 0 8px; }
.info-card p { font-size: 14px; color: var(--ink-soft); }

/* ---------- 联系页 ---------- */
.contact-grid { display: grid; grid-template-columns: 1fr 1.2fr; gap: 44px; align-items: start; }
.contact-item { display: flex; gap: 18px; padding: 20px 0; border-bottom: 1px dashed var(--line); }
.contact-item .ci-icon {
  width: 48px; height: 48px; flex: none;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  display: flex; align-items: center; justify-content: center;
  background: var(--white);
  font-size: 20px;
}
.contact-item h3 { font-size: 16px; }
.contact-item p { font-size: 14px; color: var(--ink-soft); }

.form-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 34px;
}
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.field { margin-bottom: 16px; }
.field label {
  display: block;
  font-size: 13px;
  font-weight: 600;
  margin-bottom: 7px;
  color: var(--ink-soft);
}
.field input, .field select, .field textarea {
  width: 100%;
  border: 1px solid var(--line-strong);
  background: var(--paper);
  border-radius: var(--radius);
  padding: 12px 14px;
  font-family: inherit;
  font-size: 14.5px;
  color: var(--ink);
  transition: border-color 0.2s, box-shadow 0.2s;
}
.field input:focus, .field select:focus, .field textarea:focus {
  outline: none;
  border-color: var(--accent-2);
  box-shadow: 0 0 0 3px rgba(15, 123, 108, 0.14);
}
.field textarea { resize: vertical; min-height: 120px; }
.form-ok {
  display: none;
  border: 1px dashed var(--accent-2);
  background: rgba(15, 123, 108, 0.08);
  color: var(--accent-2-deep);
  padding: 14px 16px;
  border-radius: var(--radius);
  font-size: 14px;
  margin-top: 14px;
}
.form-ok.show { display: block; }

/* ---------- 购物车抽屉 ---------- */
.cart-mask {
  position: fixed;
  inset: 0;
  background: rgba(22, 33, 29, 0.5);
  opacity: 0;
  visibility: hidden;
  transition: 0.3s;
  z-index: 200;
}
.cart-mask.open { opacity: 1; visibility: visible; }
.cart-drawer {
  position: fixed;
  top: 0; right: 0; bottom: 0;
  width: min(440px, 94vw);
  background: var(--white);
  z-index: 210;
  transform: translateX(105%);
  transition: transform 0.35s cubic-bezier(0.22, 1, 0.36, 1);
  display: flex;
  flex-direction: column;
  box-shadow: -20px 0 60px rgba(22, 33, 29, 0.2);
}
.cart-drawer.open { transform: translateX(0); }
.cart-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 24px;
  border-bottom: 1px solid var(--line);
}
.cart-head h3 { font-size: 19px; }
.cart-close {
  background: none;
  border: 1px solid var(--line);
  width: 34px; height: 34px;
  border-radius: 50%;
  font-size: 15px;
  color: var(--ink-soft);
  transition: 0.2s;
}
.cart-close:hover { border-color: var(--accent); color: var(--accent-deep); transform: rotate(90deg); }
.cart-list { flex: 1; overflow-y: auto; padding: 10px 24px; }
.cart-empty {
  text-align: center;
  padding: 60px 20px;
  color: var(--ink-faint);
}
.cart-empty .ce-icon { font-size: 40px; margin-bottom: 10px; }
.cart-item {
  display: flex;
  gap: 14px;
  padding: 16px 0;
  border-bottom: 1px dashed var(--line);
  align-items: center;
}
.cart-item .ci-svg { width: 64px; height: 64px; flex: none; background: var(--paper-2); border-radius: var(--radius); padding: 8px; border: 1px solid var(--line); }
.cart-item .ci-info { flex: 1; min-width: 0; }
.cart-item .ci-name { font-size: 14.5px; font-weight: 600; }
.cart-item .ci-code { font-family: var(--font-mono); font-size: 10.5px; color: var(--ink-faint); letter-spacing: 0.1em; }
.cart-item .ci-price { font-family: var(--font-mono); font-size: 13px; color: var(--accent-deep); margin-top: 4px; }
.qty { display: flex; align-items: center; gap: 10px; font-family: var(--font-mono); }
.qty button {
  width: 26px; height: 26px;
  border: 1px solid var(--line-strong);
  background: var(--paper);
  border-radius: 4px;
  font-size: 14px;
  color: var(--ink);
  line-height: 1;
  transition: 0.15s;
}
.qty button:hover { border-color: var(--accent); color: var(--accent-deep); }
.qty .qv { min-width: 22px; text-align: center; font-size: 13.5px; }
.ci-remove {
  background: none;
  border: none;
  color: var(--ink-faint);
  font-size: 17px;
  padding: 6px;
  transition: 0.15s;
}
.ci-remove:hover { color: var(--accent); }

.cart-foot {
  border-top: 1px solid var(--line);
  padding: 20px 24px;
  background: var(--paper);
}
.cart-total {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 14px;
  font-size: 15px;
}
.cart-total b { font-family: var(--font-mono); font-size: 26px; color: var(--accent-deep); }
.cart-foot .btn { width: 100%; justify-content: center; }
.cart-note { font-size: 11.5px; color: var(--ink-faint); margin-top: 10px; text-align: center; font-family: var(--font-mono); }

/* ---------- 结算弹窗 ---------- */
.modal-mask {
  position: fixed;
  inset: 0;
  background: rgba(22, 33, 29, 0.55);
  z-index: 300;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  opacity: 0;
  visibility: hidden;
  transition: 0.25s;
}
.modal-mask.open { opacity: 1; visibility: visible; }
.modal {
  background: var(--white);
  border-radius: var(--radius);
  width: min(520px, 100%);
  max-height: 90vh;
  overflow-y: auto;
  transform: translateY(24px);
  transition: 0.3s;
}
.modal-mask.open .modal { transform: translateY(0); }
.modal-head {
  padding: 22px 28px;
  border-bottom: 1px solid var(--line);
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.modal-head h3 { font-size: 19px; }
.modal-body { padding: 24px 28px; }
.modal-summary {
  border: 1px dashed var(--line-strong);
  background: var(--paper);
  border-radius: var(--radius);
  padding: 16px 18px;
  margin-bottom: 20px;
  font-size: 13.5px;
}
.modal-summary .row { display: flex; justify-content: space-between; padding: 4px 0; }
.modal-summary .row.total { border-top: 1px dashed var(--line-strong); margin-top: 8px; padding-top: 10px; font-weight: 700; }
.modal-summary .row.total b { font-family: var(--font-mono); font-size: 20px; color: var(--accent-deep); }

.checkout-ok { text-align: center; padding: 30px 10px; }
.checkout-ok .ok-icon {
  width: 64px; height: 64px;
  border-radius: 50%;
  background: var(--accent-2);
  color: #fff;
  font-size: 30px;
  display: flex; align-items: center; justify-content: center;
  margin: 0 auto 18px;
  animation: pop 0.4s ease;
}
.checkout-ok h3 { font-size: 22px; margin-bottom: 8px; }
.checkout-ok p { color: var(--ink-soft); font-size: 14px; }
.checkout-ok .oid {
  font-family: var(--font-mono);
  background: var(--paper-2);
  border: 1px dashed var(--line-strong);
  padding: 8px 16px;
  border-radius: 4px;
  display: inline-block;
  margin-top: 12px;
  font-size: 13px;
  letter-spacing: 0.08em;
}

/* ---------- 滚动显现 ---------- */
.reveal { opacity: 0; transform: translateY(28px); transition: opacity 0.7s ease, transform 0.7s ease; }
.reveal.in { opacity: 1; transform: none; }
.reveal-d1 { transition-delay: 0.08s; }
.reveal-d2 { transition-delay: 0.16s; }
.reveal-d3 { transition-delay: 0.24s; }
.reveal-d4 { transition-delay: 0.32s; }

/* ---------- 响应式 ---------- */
@media (max-width: 1024px) {
  .biz-grid { grid-template-columns: repeat(2, 1fr); }
  .course-grid { grid-template-columns: repeat(2, 1fr); }
  .product-grid { grid-template-columns: repeat(2, 1fr); }
  .hero-grid { grid-template-columns: 1fr; gap: 40px; }
  .hero-art { order: -1; }
  .hero-art .robot-wrap { width: min(340px, 100%); }
  .split { grid-template-columns: 1fr; gap: 40px; }
  .data-band { grid-template-columns: repeat(2, 1fr); }
  .data-band .cell:nth-child(2) { border-right: none; }
  .data-band .cell:nth-child(-n+2) { border-bottom: 1px solid rgba(255,253,248,0.14); }
  .steps { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .info-grid { grid-template-columns: repeat(2, 1fr); }
  .contact-grid { grid-template-columns: 1fr; }
}

@media (max-width: 720px) {
  .section { padding: 64px 0; }
  .nav-toggle { display: block; }
  .nav-links {
    position: fixed;
    top: 72px; left: 0; right: 0;
    background: var(--paper);
    border-bottom: 1px solid var(--line);
    flex-direction: column;
    align-items: stretch;
    padding: 12px 20px 20px;
    gap: 4px;
    transform: translateY(-12px);
    opacity: 0;
    visibility: hidden;
    transition: 0.25s;
    box-shadow: var(--shadow-2);
  }
  .nav-links.open { transform: none; opacity: 1; visibility: visible; }
  .nav-links a { padding: 12px 10px; border-bottom: 1px dashed var(--line); border-radius: 0; }
  .nav-links a.active::after { display: none; }
  .biz-grid, .course-grid, .product-grid, .steps, .info-grid { grid-template-columns: 1fr; }
  .form-row { grid-template-columns: 1fr; }
  .hero-stats { flex-wrap: wrap; }
  .hero-stats .stat { flex: 1 1 45%; border-bottom: 1px solid var(--line); }
  .data-band { grid-template-columns: 1fr 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: 28px; }
  .topbar .wrap span:last-child { display: none; }
  .hero h1 .hl { white-space: normal; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; }
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; }
}

/* ============================================================
   V2 追加：在线课堂 / 加盟 / 课程大纲 / 导航适配
   ============================================================ */

/* 导航 7 项适配 */
.nav-links a { padding: 8px 11px; font-size: 14.5px; }
.nav-actions .cart-btn { padding: 9px 13px; }
@media (max-width: 1180px) {
  .nav-links a { padding: 8px 8px; font-size: 13.5px; }
}

/* 课程类型角标（购物车内） */
.ci-type {
  display: inline-block;
  background: rgba(15, 123, 108, 0.12);
  color: var(--accent-2-deep);
  font-size: 10px;
  padding: 1px 7px;
  border-radius: 3px;
  margin-left: 4px;
  letter-spacing: 0.04em;
}

/* 课程方向卡（Track） */
.track-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.track-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: transform 0.25s, box-shadow 0.25s;
  position: relative;
}
.track-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-2); }
.track-ribbon {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--accent);
  padding: 12px 20px 0;
}
.track-media {
  background:
    radial-gradient(circle at 70% 20%, rgba(228, 85, 45, 0.1), transparent 55%),
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px),
    var(--paper-2);
  background-size: auto, 30px 30px, 30px 30px, auto;
  margin: 12px 20px 0;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px;
  display: flex;
  align-items: center;
  justify-content: center;
}
.track-media svg { width: 72%; height: 72%; transition: transform 0.4s ease; }
.track-card:hover .track-media svg { transform: scale(1.06); }
.track-body { padding: 18px 20px 22px; flex: 1; display: flex; flex-direction: column; }
.track-body h3 { font-size: 19px; margin-bottom: 8px; }
.track-body p { font-size: 13.5px; color: var(--ink-soft); flex: 1; }
.track-meta {
  display: flex;
  gap: 16px;
  margin: 14px 0;
  font-family: var(--font-mono);
  font-size: 11.5px;
  color: var(--ink-soft);
}
.track-meta b { color: var(--accent-deep); font-size: 14px; }
.track-foot {
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-top: 1px dashed var(--line);
  padding-top: 14px;
}

/* 就业方向标签 */
.job-strip { display: flex; flex-wrap: wrap; gap: 12px; }
.job-tag {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.04em;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  padding: 8px 18px;
  background: var(--white);
  color: var(--ink-soft);
}
.job-tag b { color: var(--accent-deep); font-weight: 600; }

/* 课程大纲折叠（阶段式） */
.curriculum { max-width: 900px; margin: 0 auto; }
.curriculum details {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--white);
  margin-bottom: 14px;
  overflow: hidden;
  transition: box-shadow 0.25s;
}
.curriculum details[open] { box-shadow: var(--shadow-1); }
.curriculum summary {
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 20px 24px;
  position: relative;
}
.curriculum summary::-webkit-details-marker { display: none; }
.curriculum summary .st-num {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--accent);
  letter-spacing: 0.14em;
  flex: none;
}
.curriculum summary .st-name { font-family: var(--font-serif); font-size: 18px; font-weight: 700; flex: 1; }
.curriculum summary .st-hours {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--ink-faint);
  background: var(--paper-2);
  border: 1px solid var(--line);
  padding: 4px 12px;
  border-radius: 999px;
  flex: none;
}
.curriculum summary .st-arrow {
  flex: none;
  width: 26px; height: 26px;
  border: 1px solid var(--line-strong);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  transition: transform 0.25s;
  color: var(--ink-soft);
}
.curriculum details[open] summary .st-arrow { transform: rotate(90deg); color: var(--accent); border-color: var(--accent); }
.curriculum .st-body { padding: 4px 24px 22px 84px; }
.curriculum .st-body li {
  display: flex;
  gap: 12px;
  padding: 8px 0;
  border-bottom: 1px dashed var(--line);
  font-size: 14.5px;
  color: var(--ink-soft);
  align-items: baseline;
}
.curriculum .st-body li:last-child { border-bottom: none; }
.curriculum .st-body .mod { color: var(--ink); font-weight: 600; flex: none; min-width: 150px; }
.curriculum .st-body .gh { font-family: var(--font-mono); font-size: 11px; color: var(--accent-2); flex: none; }

/* 在线课程卡 */
.oc-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.oc-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: transform 0.25s, box-shadow 0.25s;
}
.oc-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-2); }
.oc-card.hot::after {
  content: "热销";
  position: absolute;
  top: 14px; right: 14px;
  background: var(--accent);
  color: #fff;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  padding: 4px 10px;
  border-radius: 3px;
  z-index: 2;
}
.oc-media {
  background:
    radial-gradient(circle at 70% 20%, rgba(15, 123, 108, 0.12), transparent 55%),
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px),
    var(--paper-2);
  background-size: auto, 30px 30px, 30px 30px, auto;
  aspect-ratio: 16 / 8;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px;
}
.oc-media svg { width: 62%; height: 62%; transition: transform 0.4s ease; }
.oc-card:hover .oc-media svg { transform: scale(1.06) rotate(-1.5deg); }
.oc-info { padding: 20px 22px 22px; display: flex; flex-direction: column; flex: 1; }
.oc-top { display: flex; justify-content: space-between; align-items: center; }
.oc-level {
  font-size: 11px;
  font-family: var(--font-mono);
  letter-spacing: 0.14em;
  color: var(--accent-deep);
  background: rgba(228, 85, 45, 0.1);
  padding: 3px 10px;
  border-radius: 3px;
}
.oc-code { font-family: var(--font-mono); font-size: 11px; color: var(--ink-faint); letter-spacing: 0.14em; }
.oc-info h3 { font-size: 18px; margin: 10px 0 6px; line-height: 1.4; }
.oc-tagline { font-size: 13px; color: var(--ink-soft); }
.oc-tags { display: flex; flex-wrap: wrap; gap: 6px; margin: 12px 0; }
.oc-tags span {
  font-size: 11.5px;
  color: var(--accent-2-deep);
  background: rgba(15, 123, 108, 0.1);
  border: 1px solid rgba(15, 123, 108, 0.25);
  padding: 2px 9px;
  border-radius: 3px;
}
.oc-meta { font-family: var(--font-mono); font-size: 11.5px; color: var(--ink-faint); margin-bottom: 14px; }
.oc-buy {
  margin-top: auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  border-top: 1px dashed var(--line);
  padding-top: 14px;
}

/* 试看播放器弹窗 */
.player {
  position: relative;
  background:
    radial-gradient(circle at 30% 30%, rgba(15, 123, 108, 0.25), transparent 60%),
    linear-gradient(var(--grid-strong) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-strong) 1px, transparent 1px),
    var(--ink);
  background-size: auto, 34px 34px, 34px 34px, auto;
  border-radius: var(--radius);
  aspect-ratio: 16 / 9;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}
.player-art { width: 44%; opacity: 0.85; }
.player-play {
  position: absolute;
  width: 64px; height: 64px;
  border-radius: 50%;
  background: var(--accent);
  color: #fff;
  font-size: 22px;
  display: flex;
  align-items: center;
  justify-content: center;
  padding-left: 5px;
  box-shadow: 0 8px 26px rgba(228, 85, 45, 0.5);
  cursor: pointer;
  transition: transform 0.2s;
}
.player-play:hover { transform: scale(1.1); }
.player-time {
  position: absolute;
  left: 16px; bottom: 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: #9fb0a8;
}
.player-note {
  margin-top: 14px;
  font-size: 12px;
  color: var(--ink-faint);
  text-align: center;
  border: 1px dashed var(--line);
  border-radius: 4px;
  padding: 8px;
  font-family: var(--font-mono);
}

/* 加盟页 */
.adv-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.adv-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 28px 26px;
  position: relative;
  transition: transform 0.25s, box-shadow 0.25s;
}
.adv-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-2); }
.adv-card .an {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--accent);
  letter-spacing: 0.2em;
}
.adv-card h3 { font-size: 18px; margin: 10px 0 8px; }
.adv-card p { font-size: 13.5px; color: var(--ink-soft); }

.cond-list { max-width: 760px; }
.cond-list li {
  display: flex;
  gap: 16px;
  padding: 15px 0;
  border-bottom: 1px dashed var(--line);
  align-items: baseline;
}
.cond-list .ck {
  flex: none;
  width: 26px; height: 26px;
  border-radius: 50%;
  background: rgba(15, 123, 108, 0.12);
  color: var(--accent-2-deep);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 13px;
  font-weight: 700;
}
.cond-list b { display: block; }
.cond-list span { font-size: 13.5px; color: var(--ink-soft); }

@media (max-width: 1024px) {
  .oc-grid, .track-grid, .adv-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 720px) {
  .oc-grid, .track-grid, .adv-grid { grid-template-columns: 1fr; }
  .curriculum .st-body { padding-left: 24px; }
  .curriculum summary { flex-wrap: wrap; gap: 8px; }
  .curriculum summary .st-name { flex-basis: 100%; order: -1; }
}

/* ============================================================
   V4 营销化：清华背书 / 信任区 / 案例 / 优惠 / FAQ / 悬浮咨询
   ============================================================ */

/* 信任条（清华背书） */
.trust-strip {
  border: 1px solid var(--line);
  background: var(--white);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px 24px;
  padding: 14px 22px;
  margin-top: 26px;
  max-width: 640px;
  box-shadow: var(--shadow-1);
}
.trust-strip .tt {
  display: flex;
  align-items: center;
  gap: 9px;
  font-size: 13.5px;
  font-weight: 600;
  color: var(--ink);
}
.trust-strip .tt .dot {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--accent);
  flex: none;
}
.trust-strip .tt b { color: var(--accent-deep); }

/* 全宽清华横幅（移动首页用） */
.thu-banner {
  background: var(--ink);
  color: var(--paper);
  border-radius: var(--radius);
  padding: 22px 20px;
  display: flex;
  align-items: center;
  gap: 16px;
  margin-top: 18px;
  position: relative;
  overflow: hidden;
}
.thu-banner::after {
  content: "清华 x-lab";
  position: absolute;
  right: -14px; bottom: -18px;
  font-family: var(--font-serif);
  font-size: 64px;
  font-weight: 700;
  color: rgba(255, 253, 248, 0.06);
  letter-spacing: 0.05em;
}
.thu-banner .tb-icon {
  width: 46px; height: 46px;
  flex: none;
  border-radius: 50%;
  background: rgba(228, 85, 45, 0.16);
  border: 1px solid rgba(228, 85, 45, 0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
}
.thu-banner b { color: #5ec4b2; font-size: 15px; display: block; }
.thu-banner span { font-size: 12.5px; color: #b9c6c0; }

/* 优惠横幅 */
.offer-bar {
  background: linear-gradient(90deg, var(--accent), #f0783f);
  color: #fff;
  border-radius: var(--radius);
  padding: 16px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  flex-wrap: wrap;
  box-shadow: 0 10px 26px rgba(228, 85, 45, 0.3);
}
.offer-bar .ob-t {
  font-family: var(--font-serif);
  font-size: 19px;
  font-weight: 700;
  display: flex;
  align-items: center;
  gap: 12px;
}
.offer-bar .ob-t .fire { font-size: 22px; }
.offer-bar .ob-s { font-size: 13px; opacity: 0.92; margin-top: 3px; }
.offer-bar .btn { background: #fff; color: var(--accent-deep); }
.offer-bar .btn:hover { background: var(--paper); }

/* 学员案例 */
.case-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.case-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 26px 24px;
  position: relative;
  transition: transform 0.25s, box-shadow 0.25s;
}
.case-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-2); }
.case-card .quote {
  font-size: 14px;
  color: var(--ink-soft);
  line-height: 1.9;
  margin-bottom: 18px;
}
.case-card .quote::before {
  content: "“";
  font-family: var(--font-serif);
  font-size: 34px;
  color: var(--accent);
  display: block;
  line-height: 0.6;
  margin-bottom: 10px;
}
.case-card .who {
  display: flex;
  align-items: center;
  gap: 12px;
  border-top: 1px dashed var(--line);
  padding-top: 16px;
}
.case-card .avatar {
  width: 42px; height: 42px;
  border-radius: 50%;
  background: var(--ink);
  color: var(--paper);
  font-family: var(--font-serif);
  font-size: 15px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex: none;
}
.case-card .nm { font-size: 14px; font-weight: 700; }
.case-card .jb { font-size: 12px; color: var(--ink-faint); }
.case-card .sal {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--accent-deep);
  background: rgba(228, 85, 45, 0.08);
  border: 1px solid rgba(228, 85, 45, 0.3);
  padding: 4px 10px;
  border-radius: 999px;
  white-space: nowrap;
}

/* 资质 / 合作文字墙 */
.cred-wall {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  justify-content: center;
}
.cred-wall .cred {
  font-family: var(--font-serif);
  font-size: 14px;
  font-weight: 600;
  color: var(--ink-soft);
  border: 1px solid var(--line-strong);
  background: var(--white);
  padding: 10px 20px;
  border-radius: 999px;
  letter-spacing: 0.04em;
}

/* 课程保障（营销） */
.guarantee-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.guarantee {
  border: 1px dashed var(--line-strong);
  border-radius: var(--radius);
  background: rgba(255, 253, 248, 0.7);
  padding: 20px 18px;
  text-align: center;
}
.guarantee .g-ic { font-size: 26px; }
.guarantee h4 { font-size: 15px; margin: 8px 0 4px; }
.guarantee p { font-size: 12.5px; color: var(--ink-faint); }

/* 悬浮咨询 + 微信弹窗 */
.float-cta {
  position: fixed;
  right: 22px; bottom: 26px;
  z-index: 180;
  display: flex;
  flex-direction: column;
  gap: 10px;
  align-items: flex-end;
}
.float-cta .f-btn {
  display: flex;
  align-items: center;
  gap: 9px;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 999px;
  padding: 13px 20px;
  font-size: 14.5px;
  font-weight: 700;
  box-shadow: 0 10px 26px rgba(228, 85, 45, 0.4);
  transition: transform 0.2s, box-shadow 0.2s;
  animation: floaty 4s ease-in-out infinite;
}
.float-cta .f-btn:hover { transform: scale(1.05); }
.float-cta .f-btn.wechat { background: var(--accent-2); box-shadow: 0 10px 26px rgba(15, 123, 108, 0.4); animation: none; }

.wechat-modal .modal { width: min(360px, 94vw); text-align: center; }
.wechat-qr {
  width: 180px; height: 180px;
  margin: 10px auto 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background:
    repeating-linear-gradient(0deg, var(--ink) 0 6px, transparent 6px 12px),
    repeating-linear-gradient(90deg, var(--ink) 0 6px, transparent 6px 12px);
  background-size: 24px 24px;
  position: relative;
}
.wechat-qr::after {
  content: "二维码占位";
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(246, 243, 236, 0.88);
  font-size: 13px;
  color: var(--ink-faint);
  letter-spacing: 0.08em;
}
.wechat-modal .wx-id {
  font-family: var(--font-mono);
  font-size: 14px;
  background: var(--paper-2);
  border: 1px dashed var(--line-strong);
  border-radius: 4px;
  padding: 8px 14px;
  display: inline-block;
  margin-bottom: 6px;
  letter-spacing: 0.08em;
}

@media (max-width: 1024px) {
  .case-grid, .guarantee-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 720px) {
  .case-grid, .guarantee-grid { grid-template-columns: 1fr; }
  .trust-strip { padding: 12px 14px; }
  .offer-bar { padding: 14px 16px; }
  .offer-bar .ob-t { font-size: 16px; }
  .float-cta { right: 14px; bottom: calc(var(--tab-h) + 12px); }
  .float-cta .f-btn { padding: 11px 16px; font-size: 13.5px; }
  .float-cta .f-btn.wechat { display: none; }
}

/* ============================================================
   清华大学风格主题覆盖（V8）
   参考清华官网视觉语言：清华紫 #660874 · 清华红 #B01F24
   米白底 · 宋体标题 · 庄重克制 · 红条点缀
   ============================================================ */
:root {
  --paper: #FDFCFB;
  --paper-2: #F5F1FA;
  --paper-3: #ECE6F4;
  --ink: #221D2B;
  --ink-soft: #4C4656;
  --ink-faint: #8A8494;
  --accent: #660874;
  --accent-deep: #4A0E63;
  --accent-2: #B01F24;
  --accent-2-deep: #8A1420;
  --line: #E4DFEC;
  --line-strong: #C9C2D6;
  --white: #FFFFFF;
  --grid: rgba(102, 8, 116, 0.05);
  --grid-strong: rgba(102, 8, 116, 0.09);
  --shadow-1: 0 2px 10px rgba(74, 14, 99, 0.08);
  --shadow-2: 0 14px 40px rgba(74, 14, 99, 0.16);
  --radius: 4px;
}
body { background: var(--paper); }
::selection { background: var(--accent); color: #fff; }

/* 头部：清华红顶条 + 白色基底 */
.site-header { background: #fff; }
.site-header::before {
  content: ""; position: absolute; top: 0; left: 0; right: 0; height: 3px;
  background: linear-gradient(90deg, var(--accent-2) 0%, var(--accent-2) 62%, var(--accent) 62%);
}
.topbar { background: linear-gradient(90deg, var(--accent-deep), var(--accent)); }
.topbar b { color: #F5C6C8; font-weight: 700; }

/* 导航：紫字红下划线（清华官网式） */
.nav-links a { position: relative; color: var(--ink); font-weight: 500; background: none !important; }
.nav-links a::after {
  content: ""; position: absolute; left: 50%; bottom: 2px; width: 0; height: 2px;
  background: var(--accent-2); transform: translateX(-50%); transition: width .25s;
}
.nav-links a:hover { color: var(--accent-2); }
.nav-links a:hover::after, .nav-links a.active::after { left: 50% !important; right: auto !important; width: 62% !important; transform: translateX(-50%); }
.nav-links a.active { color: var(--accent); font-weight: 700; background: none !important; }

/* 按钮：紫色系 */
.btn { border-radius: var(--radius); }
.btn--accent { background: linear-gradient(135deg, var(--accent), var(--accent-deep)); box-shadow: 0 4px 14px rgba(102, 8, 116, .22); }
.btn--accent:hover { background: var(--accent-deep); box-shadow: 0 6px 18px rgba(102, 8, 116, .3); }
.btn--ghost { border-color: var(--accent); color: var(--accent); }
.btn--ghost:hover { border-color: var(--accent-deep); color: var(--accent-deep); background: var(--paper-2); }

/* Hero：淡紫氛围 + 校训座右铭 */
.hero { background: linear-gradient(180deg, #F6F2FA 0%, var(--paper) 100%); }
.hero-kicker { color: var(--accent-2); }
.hero-kicker::before { color: var(--accent); }
.hero h1 .hl { color: var(--accent-2); }
.hero h1 .hl::after { background: rgba(176, 31, 36, 0.12); }
.hero-motto {
  font-family: var(--font-serif);
  font-size: 20px;
  font-weight: 700;
  letter-spacing: 0.42em;
  color: var(--accent);
  margin: -8px 0 16px;
}

/* 数据带：紫渐变 */
.data-band { background: linear-gradient(120deg, var(--accent-deep), var(--accent)); border-radius: 0; }
.data-band .num { color: #fff; }
.data-band .lbl { color: rgba(255, 255, 255, 0.78); }
.data-band .cell { border-right-color: rgba(255, 255, 255, 0.18); }

/* CTA 横幅：红紫双色 */
.cta-band { background: linear-gradient(120deg, var(--accent-2), var(--accent)); }
.cta-band h2 { color: #fff; }
.cta-band p { color: rgba(255, 255, 255, 0.9); }

/* 区块标题：红色点缀短横 */
.section-head--center .h-title::after {
  content: ""; display: block; width: 56px; height: 3px;
  background: var(--accent-2); margin: 16px auto 0;
}

/* 页脚：深紫 */
.site-footer { background: var(--accent-deep); }
.site-footer .footer-grid a:hover { color: #F5C6C8; }
.site-footer .footer-bottom { border-top-color: rgba(255, 255, 255, 0.15); }

/* 数据带数字/标签强制白色（覆盖行内样式，V8 修复） */
.data-band .num { color: #fff !important; }
.data-band .lbl { color: rgba(255, 255, 255, 0.85) !important; }

/* V8.2 对比度修复：深色渐变条上的幽灵按钮改为白字白边 */
.cta-band .btn--ghost,
.data-band .btn--ghost,
.section--dark .btn--ghost,
.topbar .btn--ghost,
.site-footer .btn--ghost {
  border-color: rgba(255, 255, 255, 0.9);
  color: #fff;
  background: rgba(255, 255, 255, 0.06);
}
.cta-band .btn--ghost:hover,
.data-band .btn--ghost:hover,
.section--dark .btn--ghost:hover,
.topbar .btn--ghost:hover {
  background: rgba(255, 255, 255, 0.16);
  border-color: #fff;
  color: #fff;
}

/* V8.2 顶部条文字提亮（紫底上原灰绿字偏暗） */
.topbar { color: rgba(255, 255, 255, 0.9); }
.topbar a { color: rgba(255, 255, 255, 0.95); }
.topbar a:hover { color: #fff; }

/* ============================================================
   V15 动效功能层（清华浅色主题 + 翻页/3D 特效，不含深色配色）
   ============================================================ */
/* 分类筛选栏（商城/在线课堂） */
.filter-bar { display: flex; flex-wrap: wrap; gap: 10px; }
.f-chip {
  border: 1px solid var(--line-strong);
  background: #fff;
  color: var(--ink-soft);
  border-radius: 999px;
  padding: 8px 18px;
  font-size: 13.5px;
  font-weight: 600;
  transition: all 0.25s;
}
.f-chip:hover { border-color: var(--accent); color: var(--accent); }
.f-chip.on { background: var(--accent); color: #fff; border-color: transparent; }

/* 3D 翻转入场（筛选切换） */
@keyframes flipIn {
  from { opacity: 0; transform: perspective(900px) rotateY(28deg) translateY(26px) scale(0.95); }
  to { opacity: 1; transform: none; }
}
.in3d { animation: flipIn 0.55s cubic-bezier(0.22, 1, 0.36, 1) both; }

/* 页面翻页过渡（栏目切换） */
@keyframes pageFlipOut {
  0% { opacity: 1; transform: perspective(1400px) rotateY(0deg); }
  100% { opacity: 0; transform: perspective(1400px) rotateY(-88deg) translateZ(-60px); }
}
@keyframes pageFlipIn {
  0% { opacity: 0; transform: perspective(1400px) rotateY(88deg) translateZ(-60px); }
  100% { opacity: 1; transform: none; }
}
body.page-exit {
  transform-origin: left center;
  animation: pageFlipOut 0.4s ease-in forwards;
  pointer-events: none;
}
body.page-enter {
  transform-origin: left center;
  animation: pageFlipIn 0.55s cubic-bezier(0.22, 1, 0.36, 1) both;
}

/* 滚动 3D 入场 */
.reveal3d {
  opacity: 0;
  transform: perspective(900px) rotateY(14deg) translateX(24px);
  transform-origin: left center;
  transition: opacity 0.6s ease, transform 0.6s cubic-bezier(0.22, 1, 0.36, 1);
}
.reveal3d.in { opacity: 1; transform: none; }

/* 3D 卡片倾斜（仅 hover 设备，由 main.js 注入 --rx/--ry） */
.product-card, .oc-card, .track-card, .case-card, .info-card, .adv-card {
  transform-style: preserve-3d;
  transition: transform 0.18s ease, box-shadow 0.3s ease;
  will-change: transform;
}
.product-card:hover, .oc-card:hover, .track-card:hover, .case-card:hover, .info-card:hover, .adv-card:hover {
  transform: perspective(900px) rotateX(var(--rx, 0deg)) rotateY(var(--ry, 0deg)) translateY(-6px);
}

@media (prefers-reduced-motion: reduce) {
  .in3d { animation: none; }
  .product-card, .oc-card, .track-card, .case-card, .info-card, .adv-card { transform: none !important; }
  body.page-enter, body.page-exit { animation: none; }
}