/* ============================================================
   mPython VirtualBoard · 宣传站样式
   简约高级：中性色 / 细描边 / 大留白 / 单一强调色
   ============================================================ */

:root {
  --accent: #4f6df5;
  --accent-dark: #3f5bdf;
  --accent-soft: #f3f5fe;
  --ink: #0e1014;
  --ink-2: #454b57;
  --ink-3: #8a90a0;
  --line: #ececf0;
  --line-strong: #dcdde3;
  --bg: #ffffff;
  --bg-soft: #fafafb;
  --chip: #f4f4f7;
  --pcb: #232833;
  --pcb-2: #171b26;
  --gold: #d8b25c;
  --oled: #050a12;
  --oled-ink: #7dd3fc;
  --radius: 12px;
  --shadow-sm: 0 1px 2px rgba(15, 17, 26, .04);
  --shadow-md: 0 10px 30px rgba(15, 17, 26, .07);
  --shadow-lg: 0 32px 64px rgba(15, 17, 26, .16);
  --font: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", "Segoe UI", system-ui, -apple-system, sans-serif;
  --mono: "SF Mono", "Cascadia Code", Consolas, "Courier New", monospace;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font);
  font-size: 16px;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.7;
  letter-spacing: .01em;
  -webkit-font-smoothing: antialiased;
}

.container { width: min(1080px, 92%); margin: 0 auto; }

code, pre { font-family: var(--mono); }

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

/* ---------------- 按钮 ---------------- */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 12px 26px; border-radius: 999px;
  font-size: 14.5px; font-weight: 600; font-family: var(--font);
  letter-spacing: .02em;
  text-decoration: none; cursor: pointer; border: 1px solid transparent;
  transition: transform .18s ease, box-shadow .18s ease, background .18s ease, color .18s ease, border-color .18s ease;
}
.btn:active { transform: translateY(1px) scale(.98); }
.btn-sm { padding: 8px 18px; font-size: 13px; }
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: var(--accent-dark); transform: translateY(-1px); box-shadow: 0 8px 20px rgba(79, 109, 245, .28); }
.btn-outline { background: #fff; color: var(--ink); border-color: var(--line-strong); }
.btn-outline:hover { border-color: var(--ink); transform: translateY(-1px); }
.btn-ghost { background: transparent; color: var(--ink-2); border-color: var(--line-strong); }
.btn-ghost:hover { color: var(--ink); border-color: var(--ink-3); }

/* ---------------- 导航栏 ---------------- */
.nav {
  position: fixed; inset: 0 0 auto 0; z-index: 100;
  background: rgba(255, 255, 255, .8);
  backdrop-filter: blur(16px); -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid transparent;
  transition: border-color .25s ease;
}
.nav.is-scrolled { border-bottom-color: var(--line); }
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 62px; gap: 16px; }
.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; color: var(--ink); }
.brand-mark { display: grid; place-items: center; }
.brand-name { font-weight: 600; font-size: 15.5px; letter-spacing: .02em; }
.nav-links { display: flex; gap: 30px; }
.nav-links a { position: relative; color: var(--ink-2); text-decoration: none; font-size: 14px; font-weight: 500; transition: color .15s; }
.nav-links a:hover { color: var(--ink); }
.nav-links a::after {
  content: ""; position: absolute; left: 50%; bottom: -6px;
  width: 0; height: 1.5px; border-radius: 2px; background: var(--ink);
  transform: translateX(-50%); transition: width .2s ease;
}
.nav-links a.is-active { color: var(--ink); }
.nav-links a.is-active::after { width: 16px; }
.nav-actions { display: flex; align-items: center; gap: 10px; }
.lang-toggle {
  border: 1px solid var(--line-strong); background: #fff; color: var(--ink-2);
  border-radius: 999px; padding: 5px 13px; font-size: 12.5px; font-weight: 600;
  cursor: pointer; font-family: var(--font); letter-spacing: .03em; transition: all .15s;
}
.lang-toggle:hover { border-color: var(--ink); color: var(--ink); }
.nav-burger { display: none; flex-direction: column; gap: 4px; background: none; border: 0; cursor: pointer; padding: 8px; }
.nav-burger span { width: 18px; height: 1.8px; background: var(--ink); border-radius: 2px; }

/* ---------------- Hero ---------------- */
.hero {
  position: relative; overflow: hidden;
  padding: 180px 0 120px;
  background:
    radial-gradient(900px 420px at 85% -10%, rgba(79, 109, 245, .07), transparent 60%),
    radial-gradient(700px 380px at 5% 10%, rgba(125, 211, 252, .08), transparent 55%),
    var(--bg);
}
.hero::after {
  content: ""; position: absolute; inset: 0; pointer-events: none;
  background: radial-gradient(640px circle at var(--gx, 72%) var(--gy, 24%), rgba(79, 109, 245, .09), transparent 62%);
}
.hero .container { position: relative; z-index: 1; }
.hero-grid { display: grid; grid-template-columns: 1.05fr .95fr; gap: 64px; align-items: center; }
.eyebrow {
  display: inline-block; font-size: 12.5px; font-weight: 600;
  letter-spacing: .12em; color: var(--accent); margin-bottom: 22px;
}
.hero h1 { font-size: clamp(36px, 4.8vw, 56px); font-weight: 700; line-height: 1.15; letter-spacing: -.03em; margin-bottom: 22px; }
.hero-sub { font-size: 16.5px; color: var(--ink-3); max-width: 500px; margin-bottom: 38px; }
.hero-cta { display: flex; gap: 12px; flex-wrap: wrap; margin-bottom: 60px; }
.hero-stats { display: flex; gap: 48px; flex-wrap: wrap; }
.hero-stats dt { font-size: 27px; font-weight: 700; letter-spacing: -.02em; }
.hero-stats dd { font-size: 13px; color: var(--ink-3); margin-top: 1px; letter-spacing: .02em; }

/* 渐变标题关键词 */
.grad {
  background: linear-gradient(100deg, var(--accent) 5%, #38bdf8 95%);
  -webkit-background-clip: text; background-clip: text;
  -webkit-text-fill-color: transparent; color: transparent;
}

/* ---------------- CSS 手绘掌控板 ---------------- */
.hero-board { display: flex; justify-content: center; perspective: 1200px; }
.board-float { position: relative; transform-style: preserve-3d; will-change: transform; }
.hero-board .board { animation: floaty 5.5s ease-in-out infinite; }
@keyframes floaty { 0%, 100% { transform: translateY(0) rotate(-.6deg); } 50% { transform: translateY(-14px) rotate(.6deg); } }
.board-shadow {
  position: absolute; left: 10%; right: 10%; bottom: -36px; height: 26px;
  background: radial-gradient(ellipse at center, rgba(15, 17, 26, .22), transparent 70%);
  filter: blur(8px); z-index: -1;
}
.board {
  position: relative; width: 380px; height: 292px;
  background: linear-gradient(160deg, var(--pcb) 0%, var(--pcb-2) 100%);
  border-radius: 26px;
  box-shadow: var(--shadow-lg), inset 0 1px 0 rgba(255, 255, 255, .08), inset 0 -2px 6px rgba(0, 0, 0, .5);
}
.board-pins { position: absolute; left: 26px; right: 26px; height: 10px; display: flex; gap: 8px; }
.board-pins::before {
  content: ""; flex: 1;
  background-image: repeating-linear-gradient(90deg, var(--gold) 0 14px, transparent 14px 22px);
  border-radius: 3px; opacity: .9;
}
.board-pins.top { top: -5px; }
.board-pins.bottom { bottom: -5px; }
.board-oled {
  position: absolute; top: 44px; left: 50%; transform: translateX(-50%);
  width: 176px; height: 74px; background: var(--oled);
  border: 3px solid #39404e; border-radius: 8px;
  display: flex; align-items: center; justify-content: center; overflow: hidden;
  box-shadow: inset 0 0 18px rgba(125, 211, 252, .12), 0 2px 6px rgba(0, 0, 0, .4);
}
.oled-line {
  font-family: var(--mono); font-size: 14px; color: var(--oled-ink);
  text-shadow: 0 0 8px rgba(125, 211, 252, .8); white-space: nowrap;
  padding: 0 8px;
}
.board-btn {
  position: absolute; top: 132px; width: 52px; height: 52px; border-radius: 50%;
  background: radial-gradient(circle at 32% 28%, #f4d894, var(--gold) 62%, #a8843c);
  color: #4a3a15; font-weight: 800; font-size: 17px; font-family: var(--font);
  display: grid; place-items: center; border: 0; cursor: default;
  box-shadow: 0 3px 8px rgba(0, 0, 0, .45), inset 0 -3px 5px rgba(0, 0, 0, .28), inset 0 2px 3px rgba(255, 255, 255, .5);
  transition: transform .1s ease, box-shadow .1s ease;
}
.btn-a { left: 34px; }
.btn-b { right: 34px; }
.board-btn.is-live { cursor: pointer; }
.board-btn.is-live:active, .board-btn.is-pressed {
  transform: translateY(2px);
  box-shadow: 0 1px 3px rgba(0, 0, 0, .5), inset 0 3px 6px rgba(0, 0, 0, .35);
}
.board-rgb { position: absolute; top: 150px; left: 50%; transform: translateX(-50%); display: flex; gap: 16px; }
.rgb {
  width: 18px; height: 18px; border-radius: 50%;
  background: #3a4150; box-shadow: inset 0 1px 3px rgba(0, 0, 0, .5);
  transition: background .3s, box-shadow .3s;
}
.hero-board .rgb0 { animation: glow 3s ease-in-out infinite; }
.hero-board .rgb1 { animation: glow 3s ease-in-out .9s infinite; }
.hero-board .rgb2 { animation: glow 3s ease-in-out 1.8s infinite; }
@keyframes glow {
  0%, 100% { background: #3a4150; box-shadow: inset 0 1px 3px rgba(0,0,0,.5); }
  12% { background: #f43f5e; box-shadow: 0 0 14px #f43f5e, 0 0 30px rgba(244, 63, 94, .5); }
  24% { background: #f59e0b; box-shadow: 0 0 14px #f59e0b, 0 0 30px rgba(245, 158, 11, .5); }
  36% { background: #10b981; box-shadow: 0 0 14px #10b981, 0 0 30px rgba(16, 185, 129, .5); }
  48% { background: #3b82f6; box-shadow: 0 0 14px #3b82f6, 0 0 30px rgba(59, 130, 246, .5); }
  60% { background: #8b5cf6; box-shadow: 0 0 14px #8b5cf6, 0 0 30px rgba(139, 92, 246, .5); }
  72% { background: #3a4150; box-shadow: inset 0 1px 3px rgba(0,0,0,.5); }
}
.board-logo {
  position: absolute; bottom: 58px; left: 50%; transform: translateX(-50%);
  color: rgba(255, 255, 255, .38); font-size: 13px; font-weight: 700; letter-spacing: 3px;
}
.board-touch { position: absolute; bottom: 16px; left: 50%; transform: translateX(-50%); display: flex; gap: 10px; }
.board-touch span {
  width: 26px; height: 13px; border-radius: 0 0 14px 14px;
  border: 2px solid var(--gold); border-top: 0; opacity: .75;
}

/* ---------------- 通用 Section ---------------- */
.section { padding: 112px 0; }
.section:nth-of-type(even) { background: var(--bg-soft); }
.section-title { font-size: clamp(26px, 3.2vw, 36px); font-weight: 700; text-align: center; letter-spacing: -.02em; margin-bottom: 16px; }
.section-sub { text-align: center; color: var(--ink-3); font-size: 16px; max-width: 620px; margin: 0 auto 64px; }

/* ---------------- 痛点 ---------------- */
.why-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.why-card {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 36px 32px;
  transition: border-color .2s ease, transform .2s ease, box-shadow .2s ease;
}
.why-card:hover { border-color: var(--line-strong); transform: translateY(-3px); box-shadow: var(--shadow-md); }
.why-num { font-size: 12px; font-weight: 700; color: var(--ink-3); letter-spacing: .18em; margin-bottom: 16px; }
.why-card h3 { font-size: 18px; font-weight: 600; letter-spacing: -.01em; margin-bottom: 10px; }
.why-card p { color: var(--ink-3); font-size: 14.5px; }

/* ---------------- 功能 ---------------- */
.feature-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.feature-card {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 34px 30px;
  transition: border-color .2s ease, transform .2s ease, box-shadow .2s ease;
}
.feature-card:hover { border-color: var(--line-strong); transform: translateY(-3px); box-shadow: var(--shadow-md); }
.feature-icon {
  width: 44px; height: 44px; border-radius: 10px;
  background: var(--chip); color: var(--ink);
  display: grid; place-items: center; margin-bottom: 20px;
}
.feature-icon svg { width: 22px; height: 22px; }
.feature-card h3 { font-size: 17.5px; font-weight: 600; letter-spacing: -.01em; margin-bottom: 10px; }
.feature-card p { color: var(--ink-3); font-size: 14.5px; }

/* ---------------- 双版本 ---------------- */
.edition-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; max-width: 920px; margin: 0 auto; }
.edition-card {
  position: relative; background: #fff; border: 1px solid var(--line);
  border-radius: 16px; padding: 42px 38px;
  transition: border-color .2s ease, transform .2s ease, box-shadow .2s ease;
}
.edition-card:hover { border-color: var(--line-strong); transform: translateY(-3px); box-shadow: var(--shadow-md); }
.edition-tag {
  display: inline-block; font-size: 12px; font-weight: 600; letter-spacing: .04em;
  padding: 5px 12px; border-radius: 999px; margin-bottom: 20px;
}
.tag-blue { background: var(--accent-soft); color: var(--accent); }
.tag-dark { background: var(--chip); color: var(--ink-2); }
.edition-card h3 { font-size: 22px; font-weight: 700; letter-spacing: -.02em; margin-bottom: 10px; }
.edition-desc { color: var(--ink-3); font-size: 14.5px; margin-bottom: 24px; }
.edition-list { list-style: none; margin-bottom: 28px; }
.edition-list li { position: relative; padding: 7px 0 7px 26px; font-size: 14.5px; color: var(--ink-2); }
.edition-list li::before {
  content: ""; position: absolute; left: 2px; top: 14px;
  width: 12px; height: 7px; border-left: 2px solid var(--accent); border-bottom: 2px solid var(--accent);
  transform: rotate(-45deg) translateY(-2px); border-radius: 1px;
}
.edition-tech { font-family: var(--mono); font-size: 12px; color: var(--ink-3); letter-spacing: .02em; border-top: 1px solid var(--line); padding-top: 18px; }

/* ---------------- 在线体验 ---------------- */
.demo-wrap {
  display: grid; grid-template-columns: auto 1fr; gap: 64px; align-items: center;
  max-width: 960px; margin: 0 auto;
}
.demo-board-area { display: flex; justify-content: center; }
.demo-panel { min-width: 0; }
.demo-field label { display: block; font-size: 13px; font-weight: 600; color: var(--ink-2); letter-spacing: .03em; margin-bottom: 10px; }
.demo-input-row { display: flex; gap: 10px; }
.demo-input-row input {
  flex: 1; min-width: 0; border: 1px solid var(--line-strong); border-radius: 999px;
  padding: 10px 18px; font-size: 14.5px; font-family: var(--font); color: var(--ink);
  background: #fff; outline: none; transition: border-color .15s, box-shadow .15s;
}
.demo-input-row input:focus { border-color: var(--accent); box-shadow: 0 0 0 3px rgba(79, 109, 245, .14); }
.demo-actions { display: flex; gap: 10px; margin-top: 14px; flex-wrap: wrap; }
.demo-hint { font-size: 13px; color: var(--ink-3); margin: 18px 0; }
.demo-code {
  background: var(--pcb-2); color: #d6e2f0; border-radius: var(--radius);
  padding: 20px 24px; font-size: 13px; line-height: 1.75; overflow-x: auto;
}

/* ---------------- 硬件表 ---------------- */
.hw-table-wrap { max-width: 840px; margin: 0 auto; overflow-x: auto; }
.hw-table { width: 100%; border-collapse: collapse; font-size: 14.5px; }
.hw-table th, .hw-table td { padding: 15px 22px; text-align: left; border-bottom: 1px solid var(--line); }
.hw-table thead th { font-size: 12.5px; color: var(--ink-3); font-weight: 600; letter-spacing: .08em; border-bottom-color: var(--line-strong); }
.hw-table tbody tr:last-child td { border-bottom: 0; }
.hw-table tbody tr { transition: background .15s; }
.hw-table tbody tr:hover { background: var(--bg-soft); }
.hw-table code { background: var(--chip); color: var(--ink-2); padding: 3px 9px; border-radius: 6px; font-size: 12.5px; }

/* ---------------- 场景 ---------------- */
.scene-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; max-width: 920px; margin: 0 auto; }
.scene-card {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 30px 32px;
  transition: border-color .2s ease, transform .2s ease, box-shadow .2s ease;
}
.scene-card:hover { border-color: var(--line-strong); transform: translateY(-3px); box-shadow: var(--shadow-md); }
.scene-card h3 { font-size: 17px; font-weight: 600; letter-spacing: -.01em; margin-bottom: 8px; }
.scene-card p { color: var(--ink-3); font-size: 14.5px; }

/* ---------------- 快速开始 ---------------- */
.start-tabs { display: flex; justify-content: center; gap: 8px; margin-bottom: 32px; }
.start-tab {
  border: 1px solid var(--line-strong); background: #fff; color: var(--ink-2);
  padding: 9px 22px; border-radius: 999px; font-size: 14px; font-weight: 500;
  letter-spacing: .02em; cursor: pointer; font-family: var(--font); transition: all .15s;
}
.start-tab:hover { border-color: var(--ink-3); }
.start-tab.is-active { background: var(--ink); color: #fff; border-color: var(--ink); }
.start-panels { max-width: 660px; margin: 0 auto; }
.start-panel { display: none; }
.start-panel.is-active { display: block; animation: fadeUp .3s ease; }
@keyframes fadeUp { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: none; } }
.code-block {
  background: var(--pcb-2); color: #d6e2f0; border-radius: var(--radius);
  padding: 26px 30px; font-size: 13.5px; line-height: 1.85; overflow-x: auto;
}
.code-block .c { color: #79839c; }
.start-cta { text-align: center; margin-top: 40px; }

/* ---------------- 页脚 ---------------- */
.footer { border-top: 1px solid var(--line); padding: 48px 0; background: #fff; }
.footer-inner { display: flex; align-items: center; justify-content: space-between; gap: 20px; flex-wrap: wrap; }
.footer-brand p { color: var(--ink-3); font-size: 13px; margin-top: 4px; }
.footer-meta { display: flex; align-items: center; gap: 24px; font-size: 13px; color: var(--ink-3); flex-wrap: wrap; }
.footer-meta a { color: var(--ink-2); text-decoration: none; font-weight: 500; }
.footer-meta a:hover { color: var(--ink); }

/* ---------------- 滚动进场动画（支持 --d 交错延迟） ---------------- */
.reveal { opacity: 0; transform: translateY(22px); transition: opacity .6s ease var(--d, 0ms), transform .6s ease var(--d, 0ms); }
.reveal.is-visible { opacity: 1; transform: none; }

/* ---------------- 顶部滚动进度条 ---------------- */
.scroll-progress {
  position: fixed; top: 0; left: 0; z-index: 300;
  width: 0; height: 2px; background: var(--accent);
  transition: width .08s linear;
}

/* 卡片聚光灯（中性色径向高光） */
.spotlight { position: relative; overflow: hidden; }
.spotlight::after {
  content: ""; position: absolute; inset: 0; pointer-events: none;
  background: radial-gradient(340px circle at var(--mx, 50%) var(--my, 0%), rgba(79, 109, 245, .06), transparent 65%);
  opacity: 0; transition: opacity .3s ease;
}
.spotlight:hover::after { opacity: 1; }

/* 返回顶部 */
.to-top {
  position: fixed; right: 24px; bottom: 24px; z-index: 150;
  width: 42px; height: 42px; border-radius: 50%;
  border: 1px solid var(--line-strong); background: rgba(255, 255, 255, .92);
  backdrop-filter: blur(8px); -webkit-backdrop-filter: blur(8px);
  color: var(--ink-2); cursor: pointer; display: grid; place-items: center;
  box-shadow: var(--shadow-sm);
  opacity: 0; transform: translateY(12px); pointer-events: none;
  transition: opacity .25s ease, transform .25s ease, color .15s, border-color .15s;
}
.to-top.is-show { opacity: 1; transform: none; pointer-events: auto; }
.to-top:hover { color: var(--ink); border-color: var(--ink); }

/* 自定义滚动条 */
::-webkit-scrollbar { width: 9px; height: 9px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: #d6d8e0; border-radius: 6px; }
::-webkit-scrollbar-thumb:hover { background: var(--ink-3); }

/* 键盘可达性 */
:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 4px; }

/* 锚点定位补偿固定导航高度 */
section[id] { scroll-margin-top: 84px; }

@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
  .hero-board .board, .hero-board .rgb { animation: none !important; }
  .spotlight::after, .hero::after { display: none; }
  html { scroll-behavior: auto; }
}

/* ---------------- 响应式 ---------------- */
@media (max-width: 960px) {
  .hero-grid { grid-template-columns: 1fr; gap: 80px; }
  .hero { padding-top: 150px; }
  .hero-copy { text-align: center; }
  .hero-sub { margin-left: auto; margin-right: auto; }
  .hero-cta, .hero-stats { justify-content: center; }
  .why-grid, .feature-grid { grid-template-columns: repeat(2, 1fr); }
  .edition-grid, .scene-grid { grid-template-columns: 1fr; }
  .demo-wrap { grid-template-columns: 1fr; gap: 48px; }
}
@media (max-width: 640px) {
  .section { padding: 80px 0; }
  .nav-links {
    position: fixed; top: 62px; left: 0; right: 0;
    flex-direction: column; gap: 0; background: #fff;
    border-bottom: 1px solid var(--line);
    padding: 6px 0; display: none;
  }
  .nav-links.is-open { display: flex; }
  .nav-links a { padding: 13px 24px; }
  .nav-links a::after { display: none; }
  .nav-burger { display: flex; }
  .why-grid, .feature-grid { grid-template-columns: 1fr; }
  .board { width: 320px; height: 246px; border-radius: 22px; }
  .board-oled { width: 148px; height: 62px; top: 38px; }
  .oled-line { font-size: 12px; }
  .board-btn { width: 44px; height: 44px; top: 112px; font-size: 15px; }
  .btn-a { left: 26px; } .btn-b { right: 26px; }
  .board-rgb { top: 128px; gap: 13px; }
  .rgb { width: 15px; height: 15px; }
  .board-logo { bottom: 48px; font-size: 11px; }
  .hero-stats { gap: 30px; }
  .hero-stats dt { font-size: 23px; }
}