/* ============================================================
   AI 视商主播孵化平台 · 官网样式系统
   纯 CSS · 响应式 · 移动优先
   配色:冷调浅灰白 / 深蓝黑 / 科技蓝 / 青绿 / 紫
   ============================================================ */

/* ---------- 设计变量 ---------- */
:root {
  --color-paper: #f4f7fb;      /* 冷调浅灰白 - 背景 */
  --color-paper-2: #eaf0f8;    /* 次级背景 */
  --color-ink: #131a2b;        /* 深蓝黑 - 主文字 */
  --color-ink-soft: #4a5568;   /* 次级文字 */
  --color-primary: #2f6bff;    /* 科技蓝 - 主强调 */
  --color-primary-d: #1f4fd1;  /* 深蓝 */
  --color-teal: #14b8a6;       /* 青绿 - 辅助 */
  --color-violet: #7c5cff;     /* 紫 - 点缀 */
  --color-line: #dde4ef;       /* 描边 */
  --color-white: #ffffff;

  --font-serif: "Noto Serif SC", "Songti SC", "STSong", "SimSun", serif;
  --font-sans: system-ui, -apple-system, "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;

  --maxw: 1180px;
  --gap: clamp(16px, 3vw, 32px);
  --radius: 14px;
  --shadow: 0 10px 30px rgba(19, 26, 43, 0.08);
  --shadow-lg: 0 20px 50px rgba(19, 26, 43, 0.14);
  --nav-h: 68px;
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

/* ---------- 重置 ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

* { margin: 0; padding: 0; }

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
  font-family: var(--font-sans);
  color: var(--color-ink);
  background: var(--color-paper);
  line-height: 1.7;
  font-size: 16px;
  overflow-x: hidden;
}

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

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

ul { list-style: none; }

button { font-family: inherit; cursor: pointer; border: none; background: none; }

:focus-visible {
  outline: 3px solid var(--color-primary);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---------- 布局容器 ---------- */
.container {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: clamp(18px, 4vw, 40px);
}

.section { padding-block: clamp(56px, 9vw, 110px); }

.section--tint { background: var(--color-paper-2); }

/* ---------- 排版 ---------- */
h1, h2, h3, h4 {
  font-family: var(--font-serif);
  line-height: 1.25;
  font-weight: 600;
  color: var(--color-ink);
}

.eyebrow {
  font-size: 14px;
  letter-spacing: 0.28em;
  color: var(--color-primary);
  text-transform: uppercase;
  font-weight: 600;
  margin-bottom: 14px;
  display: inline-block;
}

.section-title {
  font-size: clamp(28px, 4.5vw, 44px);
  margin-bottom: 18px;
}

.section-lead {
  max-width: 60ch;
  color: var(--color-ink-soft);
  font-size: clamp(15px, 1.6vw, 18px);
}

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

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 13px 28px;
  border-radius: 999px;
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.04em;
  transition: transform 0.25s var(--ease), background 0.25s var(--ease), box-shadow 0.25s var(--ease);
  will-change: transform;
}

.btn--primary {
  background: var(--color-primary);
  color: var(--color-white);
  box-shadow: 0 8px 20px rgba(47, 107, 255, 0.28);
}
.btn--primary:hover { background: var(--color-primary-d); transform: translateY(-2px); }

.btn--ghost {
  background: transparent;
  color: var(--color-ink);
  border: 1.5px solid var(--color-ink);
}
.btn--ghost:hover { background: var(--color-ink); color: var(--color-paper); transform: translateY(-2px); }

.btn--light {
  background: var(--color-white);
  color: var(--color-ink);
}
.btn--light:hover { transform: translateY(-2px); box-shadow: var(--shadow); }

/* ---------- 顶部导航 ---------- */
.nav {
  position: fixed;
  inset: 0 0 auto 0;
  height: var(--nav-h);
  display: flex;
  align-items: center;
  z-index: 100;
  background: rgba(244, 247, 251, 0);
  transition: background 0.3s var(--ease), box-shadow 0.3s var(--ease);
}
.nav.is-scrolled {
  background: rgba(244, 247, 251, 0.92);
  backdrop-filter: blur(10px);
  box-shadow: 0 2px 18px rgba(19, 26, 43, 0.08);
}

.nav__inner {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: clamp(18px, 4vw, 40px);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 22px;
  letter-spacing: 0.06em;
  color: var(--color-ink);
}
.brand__seal {
  width: 34px;
  height: 34px;
  border-radius: 8px;
  background: var(--color-primary);
  color: var(--color-white);
  display: grid;
  place-items: center;
  font-size: 17px;
  font-weight: 700;
  flex: none;
}

.nav__links {
  display: flex;
  align-items: center;
  gap: 4px;
}
.nav__links a {
  padding: 8px 14px;
  font-size: 15px;
  border-radius: 8px;
  color: var(--color-ink-soft);
  transition: color 0.2s, background 0.2s;
}
.nav__links a:hover { color: var(--color-primary); }
.nav__links a.is-active { color: var(--color-primary); font-weight: 600; }

.nav__cta { margin-left: 10px; }

/* 汉堡按钮 */
.nav__toggle {
  display: none;
  width: 44px;
  height: 44px;
  border-radius: 10px;
  position: relative;
}
.nav__toggle span,
.nav__toggle span::before,
.nav__toggle span::after {
  content: "";
  position: absolute;
  left: 50%;
  width: 22px;
  height: 2px;
  background: var(--color-ink);
  transform: translateX(-50%);
  transition: transform 0.3s var(--ease), opacity 0.2s;
}
.nav__toggle span { top: 50%; }
.nav__toggle span::before { top: -7px; }
.nav__toggle span::after { top: 7px; }
.nav__toggle.is-open span { background: transparent; }
.nav__toggle.is-open span::before { top: 0; transform: translateX(-50%) rotate(45deg); }
.nav__toggle.is-open span::after { top: 0; transform: translateX(-50%) rotate(-45deg); }

/* ---------- Hero ---------- */
.hero {
  min-height: 100dvh;
  display: grid;
  align-items: center;
  position: relative;
  overflow: hidden;
  padding-top: var(--nav-h);
  background:
    radial-gradient(120% 90% at 80% 0%, rgba(124, 92, 255, 0.18), transparent 55%),
    radial-gradient(120% 90% at 10% 100%, rgba(20, 184, 166, 0.16), transparent 55%),
    var(--color-paper);
}
.hero__grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: var(--gap);
  align-items: center;
}
.hero__title {
  font-size: clamp(40px, 7vw, 78px);
  letter-spacing: 0.02em;
  margin-bottom: 22px;
}
.hero__title .accent { color: var(--color-primary); }
.hero__lead {
  font-size: clamp(16px, 2vw, 20px);
  color: var(--color-ink-soft);
  max-width: 46ch;
  margin-bottom: 32px;
}
.hero__actions { display: flex; flex-wrap: wrap; gap: 14px; }
.hero__stats {
  display: flex;
  gap: 36px;
  margin-top: 46px;
  flex-wrap: wrap;
}
.hero__stats .num { font-family: var(--font-serif); font-size: 34px; color: var(--color-ink); }
.hero__stats .lbl { font-size: 13px; color: var(--color-ink-soft); letter-spacing: 0.08em; }

/* Hero 视觉卡 */
.hero__visual {
  position: relative;
  aspect-ratio: 4 / 5;
  border-radius: var(--radius);
  background:
    linear-gradient(160deg, rgba(47, 107, 255, 0.85), rgba(31, 79, 209, 0.92)),
    repeating-linear-gradient(45deg, rgba(255, 255, 255, 0.05) 0 12px, transparent 12px 24px);
  box-shadow: var(--shadow-lg);
  display: grid;
  place-items: center;
  color: var(--color-white);
  overflow: hidden;
}
.hero__visual::after {
  content: "AI · 视 商";
  font-family: var(--font-serif);
  font-size: clamp(28px, 5vw, 52px);
  letter-spacing: 0.3em;
  writing-mode: vertical-rl;
  opacity: 0.92;
}
.hero__badge {
  position: absolute;
  bottom: 18px;
  left: 18px;
  background: rgba(244, 247, 251, 0.92);
  color: var(--color-ink);
  padding: 8px 14px;
  border-radius: 999px;
  font-size: 13px;
  font-weight: 600;
}

/* ---------- 卡片网格 ---------- */
.grid-cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--gap);
  margin-top: 48px;
}
.card {
  background: var(--color-white);
  border: 1px solid var(--color-line);
  border-radius: var(--radius);
  padding: 30px 26px;
  box-shadow: var(--shadow);
  transition: transform 0.3s var(--ease), box-shadow 0.3s var(--ease);
}
.card:hover { transform: translateY(-6px); box-shadow: var(--shadow-lg); }
.card__icon {
  width: 50px; height: 50px;
  border-radius: 12px;
  background: var(--color-paper-2);
  color: var(--color-primary);
  display: grid; place-items: center;
  font-size: 24px;
  margin-bottom: 18px;
}
.card__title { font-size: 21px; margin-bottom: 10px; }
.card__text { color: var(--color-ink-soft); font-size: 15px; }

/* ---------- 特性/双栏 ---------- */
.split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: clamp(28px, 5vw, 64px);
  align-items: center;
}
.split__media {
  aspect-ratio: 5 / 4;
  border-radius: var(--radius);
  background:
    linear-gradient(140deg, rgba(20, 184, 166, 0.9), rgba(124, 92, 255, 0.85)),
    repeating-linear-gradient(-45deg, rgba(255, 255, 255, 0.06) 0 14px, transparent 14px 28px);
  box-shadow: var(--shadow);
  display: grid;
  place-items: center;
  color: var(--color-white);
  font-family: var(--font-serif);
  font-size: 26px;
  letter-spacing: 0.2em;
}
.feature-list { margin-top: 26px; display: grid; gap: 16px; }
.feature-list li {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  color: var(--color-ink-soft);
}
.feature-list .tick {
  flex: none;
  width: 26px; height: 26px;
  border-radius: 50%;
  background: var(--color-teal);
  color: var(--color-white);
  display: grid; place-items: center;
  font-size: 14px;
  margin-top: 2px;
}

/* ---------- 流程步骤 ---------- */
.steps {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--gap);
  margin-top: 48px;
  counter-reset: step;
}
.step {
  position: relative;
  padding-top: 56px;
  border-top: 2px solid var(--color-line);
}
.step::before {
  counter-increment: step;
  content: "0" counter(step);
  position: absolute;
  top: 12px; left: 0;
  font-family: var(--font-serif);
  font-size: 30px;
  color: var(--color-primary);
}
.step h4 { font-size: 18px; margin-bottom: 8px; }
.step p { color: var(--color-ink-soft); font-size: 14px; }

/* ---------- 产品网格 ---------- */
.products {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--gap);
  margin-top: 48px;
}
.product {
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--color-white);
  border: 1px solid var(--color-line);
  box-shadow: var(--shadow);
  transition: transform 0.3s var(--ease);
}
.product:hover { transform: translateY(-6px); }
.product__img {
  aspect-ratio: 3 / 4;
  display: grid; place-items: center;
  color: var(--color-white);
  font-family: var(--font-serif);
  font-size: 22px;
  letter-spacing: 0.15em;
}
.product:nth-child(1) .product__img { background: linear-gradient(150deg, #2f6bff, #1f4fd1); }
.product:nth-child(2) .product__img { background: linear-gradient(150deg, #14b8a6, #0e8c7e); }
.product:nth-child(3) .product__img { background: linear-gradient(150deg, #7c5cff, #5b3fd1); }
.product__body { padding: 18px 20px 22px; }
.product__name { font-family: var(--font-serif); font-size: 18px; }
.product__price { color: var(--color-primary); font-weight: 600; margin-top: 4px; }

/* ---------- 引用/数据条 ---------- */
.quote {
  text-align: center;
  font-family: var(--font-serif);
  font-size: clamp(22px, 3.4vw, 34px);
  line-height: 1.5;
  max-width: 24ch;
  margin-inline: auto;
}
.quote span { color: var(--color-primary); }

/* ---------- 表单 ---------- */
.form {
  display: grid;
  gap: 18px;
  max-width: 560px;
}
.form__row { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.field { display: grid; gap: 7px; }
.field label { font-size: 14px; font-weight: 600; color: var(--color-ink); }
.field input,
.field textarea,
.field select {
  font-family: inherit;
  font-size: 15px;
  padding: 12px 14px;
  border: 1.5px solid var(--color-line);
  border-radius: 10px;
  background: var(--color-white);
  color: var(--color-ink);
  transition: border-color 0.2s, box-shadow 0.2s;
}
.field input:focus,
.field textarea:focus,
.field select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(47, 107, 255, 0.12);
}
.field textarea { resize: vertical; min-height: 120px; }
.field .err { color: var(--color-primary); font-size: 13px; min-height: 16px; }
.field input.is-invalid,
.field textarea.is-invalid { border-color: var(--color-primary); }

.form__note { font-size: 13px; color: var(--color-ink-soft); }
.form__status {
  padding: 14px 18px;
  border-radius: 10px;
  background: var(--color-teal);
  color: var(--color-white);
  font-size: 14px;
  display: none;
}
.form__status.is-visible { display: block; }

/* ---------- 联系信息卡 ---------- */
.contact-grid {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: clamp(28px, 5vw, 56px);
  align-items: start;
}
.info-list { display: grid; gap: 22px; }
.info-list .item { display: flex; gap: 14px; }
.info-list .ico {
  width: 44px; height: 44px; flex: none;
  border-radius: 12px;
  background: var(--color-paper-2);
  color: var(--color-primary);
  display: grid; place-items: center; font-size: 20px;
}
.info-list h4 { font-size: 16px; margin-bottom: 3px; }
.info-list p { color: var(--color-ink-soft); font-size: 14px; }

/* ---------- 页脚 ---------- */
.footer {
  background: var(--color-ink);
  color: var(--color-paper);
  padding-block: 56px 28px;
}
.footer__grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1fr;
  gap: var(--gap);
}
.footer .brand { color: var(--color-paper); }
.footer__about { color: rgba(244, 247, 251, 0.7); font-size: 14px; margin-top: 16px; max-width: 32ch; }
.footer h4 { color: var(--color-paper); font-size: 15px; margin-bottom: 14px; font-family: var(--font-sans); letter-spacing: 0.04em; }
.footer a { color: rgba(244, 247, 251, 0.72); font-size: 14px; display: block; padding: 5px 0; transition: color 0.2s; }
.footer a:hover { color: var(--color-violet); }
.footer__bottom {
  margin-top: 40px;
  padding-top: 22px;
  border-top: 1px solid rgba(244, 247, 251, 0.15);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px;
  font-size: 13px;
  color: rgba(244, 247, 251, 0.6);
}
.footer__beian a { display: inline; padding: 0; color: rgba(244, 247, 251, 0.6); }
.footer__beian a:hover { color: var(--color-violet); }

/* ---------- 内页头部 ---------- */
.page-hero {
  padding-top: calc(var(--nav-h) + clamp(48px, 8vw, 90px));
  padding-bottom: clamp(40px, 6vw, 72px);
  background:
    radial-gradient(120% 80% at 85% 0%, rgba(124, 92, 255, 0.16), transparent 55%),
    var(--color-paper-2);
}
.page-hero__title { font-size: clamp(32px, 5vw, 52px); margin-bottom: 14px; }
.page-hero__lead { color: var(--color-ink-soft); max-width: 56ch; font-size: clamp(15px, 1.6vw, 18px); }
.breadcrumb { font-size: 13px; color: var(--color-ink-soft); letter-spacing: 0.06em; margin-bottom: 18px; }
.breadcrumb a:hover { color: var(--color-primary); }

/* ---------- 滚动揭示动画 ---------- */
.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
}
.reveal.is-visible { opacity: 1; transform: none; }

/* ---------- 响应式断点 ---------- */
@media (max-width: 960px) {
  .hero__grid { grid-template-columns: 1fr; }
  .hero__visual { max-width: 420px; }
  .grid-cards,
  .products { grid-template-columns: repeat(2, 1fr); }
  .steps { grid-template-columns: repeat(2, 1fr); row-gap: 36px; }
  .footer__grid { grid-template-columns: 1fr 1fr; row-gap: 32px; }
  .contact-grid { grid-template-columns: 1fr; }
}

@media (max-width: 760px) {
  .nav__links {
    position: fixed;
    inset: var(--nav-h) 0 auto 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: rgba(244, 247, 251, 0.98);
    backdrop-filter: blur(10px);
    padding: 12px 18px 22px;
    box-shadow: 0 14px 30px rgba(19, 26, 43, 0.12);
    transform: translateY(-12px);
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.25s var(--ease), transform 0.25s var(--ease);
  }
  .nav__links.is-open { opacity: 1; transform: none; pointer-events: auto; }
  .nav__links a { padding: 14px 8px; border-bottom: 1px solid var(--color-line); }
  .nav__cta { margin: 14px 0 0; }
  .nav__toggle { display: block; }

  .split { grid-template-columns: 1fr; }
  .grid-cards,
  .products { grid-template-columns: 1fr; }
  .steps { grid-template-columns: 1fr; }
  .form__row { grid-template-columns: 1fr; }
  .footer__grid { grid-template-columns: 1fr; }
}

/* 尊重减少动态偏好 */
@media (prefers-reduced-motion: reduce) {
  * { scroll-behavior: auto !important; }
  .reveal { opacity: 1; transform: none; transition: none; }
}