/* ============================================================
   Vibe Coding 实战课 · 落地页样式
   保持原站视觉语言（浅底 + 蓝色品牌 + 圆角卡片），
   但弱化渐变/发光/动效等「悬浮感」，整体更克制、更像正常课程页。
   ============================================================ */

:root {
  --bg: #fafbfc;
  --card: #ffffff;
  --ink: #111827;
  --ink-2: #374151;
  --muted: #6b7280;
  --faint: #9aa3b2;
  --line: #e8ebf1;
  --line-2: #dde2ea;
  --brand: #2563eb;
  --brand-dark: #1d4ed8;
  --brand-soft: #f2f6ff;
  --brand-line: #d9e4fb;
  --radius: 14px;
  --radius-sm: 9px;
  --shadow: 0 1px 2px rgba(16, 24, 40, 0.04), 0 8px 24px -14px rgba(16, 24, 40, 0.14);
  --font: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB',
    'Microsoft YaHei', 'Noto Sans SC', sans-serif;
  --mono: ui-monospace, 'SF Mono', Menlo, Consolas, monospace;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
  text-decoration: none;
}

ul {
  list-style: none;
}

img {
  display: block;
  max-width: 100%;
}

::selection {
  background: var(--brand);
  color: #fff;
}

:focus-visible {
  outline: 2px solid var(--brand);
  outline-offset: 2px;
}

.wrap {
  width: min(1120px, 90vw);
  margin-inline: auto;
}

.sec {
  padding: clamp(56px, 7vw, 96px) 0;
}

.sec-alt {
  background: var(--card);
  border-block: 1px solid var(--line);
}

/* ---------- 通用：区块标题 ---------- */
.head {
  max-width: 700px;
  margin-bottom: clamp(32px, 4vw, 48px);
}

.head .kicker {
  font-size: 13px;
  font-weight: 600;
  color: var(--brand);
  margin-bottom: 10px;
}

.head h2 {
  font-size: clamp(26px, 3.6vw, 38px);
  font-weight: 700;
  line-height: 1.25;
  letter-spacing: -0.01em;
}

.head p {
  margin-top: 14px;
  color: var(--muted);
  font-size: 16px;
}

.head.center {
  margin-inline: auto;
  text-align: center;
}

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s, border-color 0.2s, box-shadow 0.2s, color 0.2s;
  white-space: nowrap;
}

.btn-sm {
  padding: 9px 18px;
  font-size: 14px;
}

.btn-lg {
  padding: 14px 28px;
}

.btn-primary {
  background: var(--brand);
  color: #fff;
}

.btn-primary:hover {
  background: var(--brand-dark);
}

.btn-ghost {
  background: #fff;
  border-color: var(--line-2);
  color: var(--ink);
}

.btn-ghost:hover {
  border-color: #c7cdd8;
}

.btn-block {
  width: 100%;
}

/* ============================================================
   Header
   ============================================================ */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(250, 251, 252, 0.9);
  backdrop-filter: saturate(180%) blur(10px);
  -webkit-backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--line);
}

.nav-inner {
  height: 66px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 16px;
}

.brand-mark {
  width: 30px;
  height: 30px;
  border-radius: 8px;
  background: var(--brand);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--mono);
  font-size: 15px;
  font-weight: 700;
}

.brand span em {
  font-style: normal;
  font-weight: 500;
  color: var(--muted);
  margin-left: 4px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 26px;
}

.nav-links a {
  font-size: 14.5px;
  color: var(--muted);
  transition: color 0.2s;
}

.nav-links a:hover {
  color: var(--ink);
}

.nav-cta {
  display: flex;
  align-items: center;
  gap: 14px;
}

.nav-toggle {
  display: none;
  background: none;
  border: 0;
  font-size: 22px;
  color: var(--ink);
  cursor: pointer;
}

/* ============================================================
   Hero
   ============================================================ */
.hero {
  padding: clamp(48px, 7vw, 88px) 0 clamp(40px, 5vw, 64px);
  background: linear-gradient(180deg, #f4f7fd 0%, var(--bg) 100%);
  border-bottom: 1px solid var(--line);
}

.hero-inner {
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.badge {
  display: inline-block;
  padding: 6px 14px;
  border-radius: 999px;
  font-size: 13px;
  color: var(--brand-dark);
  background: var(--brand-soft);
  border: 1px solid var(--brand-line);
  margin-bottom: 22px;
}

.hero h1 {
  font-size: clamp(32px, 5.4vw, 56px);
  font-weight: 700;
  line-height: 1.16;
  letter-spacing: -0.02em;
  max-width: 15em;
}

.hero h1 b {
  color: var(--brand);
  font-weight: 700;
}

.hero-sub {
  margin-top: 20px;
  font-size: clamp(15px, 1.5vw, 18px);
  line-height: 1.9;
  color: var(--muted);
  max-width: 660px;
}

.hero-btns {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
  margin-top: 30px;
}

.hero-by {
  margin-top: 18px;
  font-size: 14.5px;
  color: var(--ink-2);
}

.hero-by span {
  display: inline-block;
  margin-right: 8px;
  padding: 2px 10px;
  font-size: 12px;
  font-weight: 600;
  color: var(--brand-dark);
  background: var(--brand-soft);
  border: 1px solid var(--brand-line);
  border-radius: 999px;
}

.stats {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
  width: min(820px, 100%);
  margin-top: clamp(36px, 5vw, 52px);
}

.stat {
  padding: 20px 16px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.stat strong {
  display: block;
  font-size: clamp(26px, 3vw, 34px);
  font-weight: 700;
  letter-spacing: -0.02em;
}

.stat span {
  font-size: 13px;
  color: var(--muted);
}

.cred {
  margin-top: 20px;
  padding: 16px 18px;
  font-size: 14px;
  line-height: 1.85;
  color: var(--muted);
  background: var(--brand-soft);
  border: 1px solid var(--brand-line);
  border-radius: 12px;
}

/* ============================================================
   Features
   ============================================================ */
.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}

.feature {
  padding: 24px 22px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  transition: border-color 0.2s, box-shadow 0.2s;
}

.feature:hover {
  border-color: var(--line-2);
  box-shadow: var(--shadow);
}

.feature-ico {
  width: 38px;
  height: 38px;
  border-radius: 9px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--brand-soft);
  color: var(--brand);
  margin-bottom: 16px;
}

.feature-ico svg {
  width: 20px;
  height: 20px;
}

.feature h3 {
  font-size: 17px;
  font-weight: 600;
  margin-bottom: 7px;
}

.feature p {
  font-size: 14px;
  line-height: 1.75;
  color: var(--muted);
}

/* ============================================================
   课程大纲
   ============================================================ */
.dims {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 18px;
}

.dim {
  padding: clamp(22px, 2.6vw, 30px);
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 16px;
}

.dim-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 14px;
  margin-bottom: 12px;
}

.dim-meta {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 8px;
}

.chip {
  font-size: 12px;
  font-weight: 600;
  padding: 3px 10px;
  border-radius: 999px;
  color: var(--brand-dark);
  background: var(--brand-soft);
  border: 1px solid var(--brand-line);
}

.dim-range {
  font-size: 12px;
  color: var(--faint);
}

.dim-head h3 {
  font-size: 19px;
  font-weight: 700;
  line-height: 1.35;
}

.dim-no {
  font-size: 15px;
  font-weight: 700;
  color: var(--faint);
  font-family: var(--mono);
  padding-top: 2px;
}

.dim-sub {
  font-size: 14px;
  color: var(--muted);
  margin-bottom: 18px;
}

.chaps {
  display: grid;
  gap: 12px;
}

.chap {
  padding: 14px 16px;
  background: #fafbfd;
  border: 1px solid var(--line);
  border-radius: 12px;
}

.chap-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 10px;
}

.chap-head h4 {
  font-size: 14.5px;
  font-weight: 600;
}

.chap-head span {
  font-size: 12px;
  color: var(--faint);
  white-space: nowrap;
}

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.tag {
  font-size: 12.5px;
  padding: 4px 10px;
  border-radius: 7px;
  color: var(--ink-2);
  background: #fff;
  border: 1px solid var(--line);
}

.tag.mile {
  color: var(--brand-dark);
  background: var(--brand-soft);
  border-color: var(--brand-line);
  font-weight: 600;
}

.outline-note {
  margin-top: 22px;
  padding: 16px;
  text-align: center;
  font-size: 13.5px;
  color: var(--muted);
  background: var(--brand-soft);
  border: 1px solid var(--brand-line);
  border-radius: 12px;
}

/* ============================================================
   技术栈
   ============================================================ */
.stack {
  border-top: 1px solid var(--line);
}

.stack-row {
  display: grid;
  grid-template-columns: 190px 1fr;
  gap: clamp(16px, 3vw, 40px);
  align-items: center;
  padding: 18px 2px;
  border-bottom: 1px solid var(--line);
}

.stack-cat strong {
  display: block;
  font-size: 15px;
}

.stack-cat span {
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--faint);
}

.chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.chips li {
  font-size: 13.5px;
  padding: 6px 13px;
  border-radius: 8px;
  color: var(--ink-2);
  background: #f4f6fa;
  border: 1px solid var(--line);
}

/* ============================================================
   里程碑
   ============================================================ */
.stones {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}

.stone {
  padding: 22px 20px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.stone.mile {
  border-color: var(--brand-line);
  background: var(--brand-soft);
}

.stone-no {
  font-size: 12px;
  font-family: var(--mono);
  color: var(--faint);
}

.stone h4 {
  margin: 10px 0 5px;
  font-size: 17px;
  font-weight: 600;
}

.stone p {
  font-size: 13px;
  color: var(--muted);
  line-height: 1.65;
}

.stone-ep {
  display: inline-block;
  margin-top: 12px;
  font-size: 12px;
  color: var(--faint);
}

/* ============================================================
   赠品：脚手架
   ============================================================ */
.bonus {
  display: grid;
  grid-template-columns: 0.95fr 1.05fr;
  gap: clamp(24px, 4vw, 48px);
  align-items: center;
  padding: clamp(26px, 3.4vw, 44px);
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 18px;
}

.bonus h2 {
  font-size: clamp(24px, 3vw, 32px);
  font-weight: 700;
  line-height: 1.3;
  margin-top: 6px;
}

.bonus-desc {
  margin-top: 14px;
  font-size: 15px;
  line-height: 1.9;
  color: var(--muted);
}

.bonus-note {
  display: inline-block;
  margin-top: 16px;
  padding: 7px 14px;
  font-size: 13px;
  font-weight: 600;
  color: #b45309;
  background: #fffbeb;
  border: 1px solid #fde68a;
  border-radius: 999px;
}

.bonus-list {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.bonus-item {
  padding: 18px;
  background: #fafbfd;
  border: 1px solid var(--line);
  border-radius: 12px;
}

.bonus-item strong {
  display: block;
  font-size: 15px;
  margin-bottom: 5px;
}

.bonus-item p {
  font-size: 13px;
  line-height: 1.7;
  color: var(--muted);
}

.bonus-item b {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 22px;
  height: 22px;
  border-radius: 6px;
  font-size: 12px;
  color: var(--brand-dark);
  background: var(--brand-soft);
  margin-bottom: 10px;
}

/* ============================================================
   学习保障
   ============================================================ */
.res {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 14px;
  margin-bottom: 20px;
}

.res-item {
  padding: 22px 20px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.res-item strong {
  display: block;
  font-size: 16px;
  margin-bottom: 5px;
}

.res-item p {
  font-size: 13px;
  line-height: 1.7;
  color: var(--muted);
}

.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
}

.panel {
  padding: clamp(22px, 2.8vw, 30px);
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 16px;
}

.panel h3 {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 16px;
}

.list {
  display: grid;
  gap: 13px;
}

.list li {
  position: relative;
  padding-left: 18px;
}

.list li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 8px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--brand);
}

.list strong {
  display: block;
  font-size: 14.5px;
}

.list span {
  font-size: 13px;
  line-height: 1.7;
  color: var(--muted);
}

/* ============================================================
   FAQ
   ============================================================ */
.faq {
  display: grid;
  gap: 10px;
  max-width: 860px;
}

.qa {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 12px;
}

.qa[open] {
  border-color: var(--brand-line);
}

.qa summary {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 18px 20px;
  cursor: pointer;
  list-style: none;
  font-size: 15.5px;
  font-weight: 600;
}

.qa summary::-webkit-details-marker {
  display: none;
}

.qa .q-no {
  font-size: 12px;
  font-family: var(--mono);
  color: var(--brand);
  flex-shrink: 0;
}

.qa .q-t {
  flex: 1;
}

.qa .q-mark {
  flex-shrink: 0;
  font-size: 18px;
  line-height: 1;
  color: var(--faint);
  transition: transform 0.2s, color 0.2s;
}

.qa[open] .q-mark {
  transform: rotate(45deg);
  color: var(--brand);
}

.qa p {
  padding: 0 20px 20px 44px;
  font-size: 14px;
  line-height: 1.9;
  color: var(--muted);
}

/* ============================================================
   联系 + CTA
   ============================================================ */
.cta {
  background: #0f172a;
  color: #fff;
  text-align: center;
  padding: clamp(52px, 7vw, 88px) 0;
}

.cta-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.cta h2 {
  font-size: clamp(28px, 4vw, 46px);
  font-weight: 700;
  line-height: 1.22;
  letter-spacing: -0.01em;
}

.cta-sub {
  margin-top: 16px;
  font-size: 16px;
  color: #cbd5e1;
  max-width: 620px;
}

.cta .hero-btns {
  margin-top: 28px;
}

.btn-white {
  background: #fff;
  color: #0f172a;
}

.btn-white:hover {
  background: #eef2f7;
}

.btn-line {
  background: transparent;
  color: #fff;
  border-color: rgba(255, 255, 255, 0.35);
}

.btn-line:hover {
  border-color: #fff;
}

.qr {
  margin-top: 40px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.qr img {
  width: 200px;
  padding: 10px;
  background: #fff;
  border-radius: 14px;
}

.qr span {
  font-size: 13px;
  color: #94a3b8;
}

.trust {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px 28px;
  margin-top: 40px;
  padding-top: 26px;
  border-top: 1px solid rgba(255, 255, 255, 0.12);
  font-size: 13.5px;
  color: #cbd5e1;
}

.trust li::before {
  content: '✓ ';
  color: #4ade80;
  font-weight: 700;
}

/* ============================================================
   Footer
   ============================================================ */
.footer {
  background: #0f172a;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  padding: 28px 0;
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 14.5px;
  font-weight: 600;
  color: #fff;
}

.footer-brand .brand-mark {
  width: 26px;
  height: 26px;
  font-size: 13px;
  border-radius: 7px;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
}

.footer-links a {
  font-size: 13px;
  color: #94a3b8;
  transition: color 0.2s;
}

.footer-links a:hover {
  color: #fff;
}

.footer-copy {
  font-size: 12px;
  color: #64748b;
}

/* ============================================================
   入场（很轻，不做位移花哨）
   ============================================================ */
.reveal {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.in {
  opacity: 1;
  transform: none;
}

/* ============================================================
   响应式
   ============================================================ */
@media (max-width: 980px) {
  .grid-4,
  .res {
    grid-template-columns: repeat(2, 1fr);
  }

  .stones {
    grid-template-columns: repeat(2, 1fr);
  }

  .bonus {
    grid-template-columns: 1fr;
  }

  .stack-row {
    grid-template-columns: 1fr;
    gap: 10px;
  }
}

@media (max-width: 860px) {
  .nav-links {
    display: none;
  }

  .nav-toggle {
    display: block;
  }

  .nav.open .nav-links {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 4px;
    position: absolute;
    top: 66px;
    left: 0;
    right: 0;
    padding: 12px 5vw 18px;
    background: #fff;
    border-bottom: 1px solid var(--line);
  }

  .dims,
  .two-col {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 640px) {
  .stats {
    grid-template-columns: 1fr 1fr;
  }

  .grid-4,
  .res,
  .stones,
  .bonus-list,
  .nodes {
    grid-template-columns: 1fr;
  }

  .qa p {
    padding-left: 20px;
  }

  .nav-cta .btn {
    display: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
}

/* ============================================================
   Projects（真实项目矩阵）
   ============================================================ */
.proj-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}

.proj {
  padding: 22px 20px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  transition: border-color 0.2s, box-shadow 0.2s;
}

.proj:hover {
  border-color: var(--line-2);
  box-shadow: var(--shadow);
}

.proj h3 {
  font-size: 17px;
  font-weight: 700;
  color: var(--ink);
}

.proj-role {
  margin-top: 5px;
  font-size: 13px;
  font-weight: 600;
  color: var(--brand);
}

.proj-stack {
  margin-top: 9px;
  font-family: var(--mono);
  font-size: 12px;
  color: var(--muted);
  line-height: 1.6;
}

.proj-desc {
  margin-top: 9px;
  font-size: 13.5px;
  line-height: 1.75;
  color: var(--ink-2);
}

@media (max-width: 980px) {
  .proj-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 600px) {
  .proj-grid {
    grid-template-columns: 1fr;
  }
}

/* ============================================================
   国产 AI 编程工具（重点）
   ============================================================ */
.tools-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
}

.tool {
  padding: 22px 22px 20px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  transition: border-color 0.2s, box-shadow 0.2s;
}

.tool:hover {
  border-color: var(--brand-line);
  box-shadow: var(--shadow);
}

.tool-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 10px;
}

.tool-head h3 {
  font-size: 19px;
  font-weight: 700;
}

.tool-vendor {
  font-size: 12.5px;
  font-weight: 600;
  color: var(--brand);
}

.tool-role {
  margin-top: 6px;
  font-size: 13px;
  font-weight: 600;
  color: var(--ink-2);
}

.tool-list {
  margin-top: 14px;
  display: grid;
  gap: 7px;
}

.tool-list li {
  position: relative;
  padding-left: 16px;
  font-size: 13.5px;
  line-height: 1.65;
  color: var(--muted);
}

.tool-list li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 7px;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--brand);
}

.tool-price {
  margin-top: 16px;
  padding-top: 12px;
  border-top: 1px solid var(--line);
  font-size: 12.5px;
  font-family: var(--mono);
  color: var(--faint);
}

.model-note {
  margin-top: 18px;
  padding: 18px 22px;
  background: var(--brand-soft);
  border: 1px solid var(--brand-line);
  border-radius: 12px;
}

.model-note h3 {
  font-size: 16px;
  font-weight: 700;
  margin-bottom: 6px;
}

.model-note p {
  font-size: 14px;
  line-height: 1.8;
  color: var(--muted);
}

@media (max-width: 720px) {
  .tools-grid {
    grid-template-columns: 1fr;
  }
}