/* ============================================================
   Keecheer 奇趣实验室 — 官网样式
   明亮白底 + 橙色强调 · 克制动效 · 响应式
   ============================================================ */

:root {
  --orange: #ff6b35;
  --orange-soft: #ff8c5a;
  --orange-tint: #fff3ec;
  --ink: #16161a;
  --ink-soft: #5b5b66;
  --line: #ececf0;
  --bg: #ffffff;
  --bg-tint: #fbf7f4;
  --max: 1180px;
  --pad-x: 28px;
  --radius: 18px;
  --shadow: 0 18px 50px -22px rgba(22, 22, 26, 0.25);
  --font-en: "Space Grotesk", "Inter", -apple-system, BlinkMacSystemFont, sans-serif;
  --font-cn: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
  --font-body: var(--font-cn);
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  color: var(--ink);
  background: var(--bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

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

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

.accent { color: var(--orange); }

/* ---------- 导航 ---------- */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  transition: background 0.3s ease, box-shadow 0.3s ease;
}
.nav__inner {
  max-width: var(--max);
  margin: 0 auto;
  padding: 18px 28px;
  display: flex;
  align-items: center;
  gap: 24px;
}
.nav.scrolled {
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: saturate(180%) blur(14px);
  box-shadow: 0 1px 0 var(--line);
}
.nav__brand { display: flex; align-items: center; }
.nav__logo {
  max-height: 44px;
  width: auto;
}
.nav__links {
  display: flex;
  gap: 26px;
  margin-left: auto;
  font-size: 15px;
  color: var(--ink-soft);
}
.nav__links a { transition: color 0.2s ease; }
.nav__links a:hover { color: var(--orange); }
.nav__cta {
  background: var(--orange);
  color: #fff;
  padding: 10px 18px;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 600;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  white-space: nowrap;
}
.nav__cta:hover { transform: translateY(-2px); box-shadow: 0 10px 24px -10px var(--orange); }
.nav__right { display: flex; align-items: center; margin-left: auto; }
.nav__theme {
  width: 32px; height: 32px;
  border-radius: 50%;
  border: 1.5px solid var(--line);
  background: transparent;
  color: var(--ink);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 15px;
  line-height: 1;
  margin-right: 10px;
  transition: border-color 0.2s ease, color 0.2s ease, transform 0.2s ease;
}
.nav__theme:hover { border-color: var(--orange); color: var(--orange); transform: rotate(18deg); }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-block;
  padding: 14px 28px;
  border-radius: 999px;
  font-weight: 600;
  font-size: 15px;
  transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
}
.btn--primary { background: var(--orange); color: #fff; }
.btn--primary:hover { transform: translateY(-3px); box-shadow: 0 16px 32px -14px var(--orange); }
.btn--ghost { border: 1.5px solid var(--line); color: var(--ink); }
.btn--ghost:hover { border-color: var(--orange); color: var(--orange); }

/* ---------- Hero ---------- */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 120px 24px 80px;
  overflow: hidden;
}
.hero__glow {
  position: absolute;
  top: -10%; left: 50%;
  width: 720px; height: 720px;
  transform: translateX(-50%);
  background: radial-gradient(circle, var(--orange-tint) 0%, rgba(255,243,236,0) 65%);
  pointer-events: none;
}
.hero__inner { position: relative; max-width: 880px; z-index: 1; }
.hero__tag {
  display: inline-block;
  font-family: var(--font-en);
  letter-spacing: 0.18em;
  font-size: 13px;
  color: var(--orange);
  background: var(--orange-tint);
  padding: 7px 16px;
  border-radius: 999px;
  margin-bottom: 28px;
}
.hero__title {
  font-family: var(--font-cn);
  font-size: clamp(34px, 5.5vw, 56px);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.01em;
}
.hero__subtitle {
  font-family: var(--font-en);
  font-size: clamp(18px, 2.4vw, 26px);
  color: var(--ink-soft);
  margin-top: 14px;
  font-weight: 500;
}
.hero__lead {
  color: var(--ink-soft);
  font-size: clamp(15px, 1.6vw, 18px);
  margin: 28px auto 36px;
  max-width: 560px;
}
.hero__actions { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }
.hero__ice {
  margin: 0 auto 40px;
  width: 220px;
  animation: float 5s ease-in-out infinite;
}
.hero__ice img { width: 100%; height: auto; }
@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-14px); }
}
.hero__scroll {
  position: absolute;
  bottom: 28px; left: 50%;
  transform: translateX(-50%);
  width: 26px; height: 42px;
  border: 2px solid var(--line);
  border-radius: 14px;
}
.hero__scroll span {
  position: absolute;
  top: 8px; left: 50%;
  width: 4px; height: 8px;
  background: var(--orange);
  border-radius: 2px;
  transform: translateX(-50%);
  animation: scroll-dot 1.8s ease-in-out infinite;
}
@keyframes scroll-dot {
  0% { opacity: 0; top: 8px; }
  40% { opacity: 1; }
  100% { opacity: 0; top: 24px; }
}

/* ---------- 通用 section ---------- */
.section {
  max-width: var(--max);
  margin: 0 auto;
  padding: 110px var(--pad-x);
}
.section--tint {
  position: relative;
  z-index: 0;
  max-width: var(--max);
  margin: 0 auto;
  padding: 110px var(--pad-x);
  background: transparent;
}
/* 伪元素实现全幅背景，内容盒模型与 .section 完全一致，确保 02/04 与 01/03 严格对齐 */
.section--tint::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 100vw;
  background: var(--bg-tint);
  z-index: -1;
}
/* tint 区标题需与 01 等普通 section 一样贴左对齐 */
.section--tint > .section__head {
  margin-left: 0;
  margin-right: auto;
}
.section__head { max-width: 720px; margin-bottom: 56px; }
.eyebrow {
  font-family: var(--font-en);
  letter-spacing: 0.16em;
  font-size: 13px;
  color: var(--orange);
  font-weight: 600;
}
.section__title {
  font-size: clamp(28px, 4vw, 46px);
  font-weight: 700;
  line-height: 1.2;
  margin-top: 14px;
  letter-spacing: -0.01em;
}
.section__desc {
  color: var(--ink-soft);
  font-size: 17px;
  margin-top: 18px;
}

/* ---------- About ---------- */
.section__grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: start;
}
#about .section__title {
  font-size: clamp(24px, 3.5vw, 38px);
}
.about__lead {
  font-size: 18px;
  font-weight: 400;
  line-height: 1.6;
  color: var(--ink-soft);
  margin: 18px 0 0;
}
.about__lead strong { color: var(--orange); }
.about__body {
  display: flex;
  align-items: center;
  align-self: stretch;
}
.about__stats {
  display: flex;
  gap: 18px;
  margin-top: 0;
  flex-wrap: wrap;
}
.stat {
  flex: 1;
  min-width: 150px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px 24px;
  background: var(--bg-tint);
}
.stat__num {
  display: block;
  font-family: var(--font-en);
  font-size: 40px;
  font-weight: 700;
  color: var(--ink);
  line-height: 1;
}
.stat__label { color: var(--ink-soft); font-size: 14px; }

/* ---------- Features ---------- */
.features {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.feature {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 36px 30px;
  transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease;
}
.feature:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow);
  border-color: transparent;
}
.feature__icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 52px; height: 52px;
  border-radius: 14px;
  background: var(--orange-tint);
  color: var(--orange);
  font-size: 26px;
  margin-bottom: 20px;
}
.feature h3 { font-size: 20px; margin-bottom: 8px; }
.feature p { color: var(--ink-soft); font-size: 15px; }
.feature__more {
  display: inline-block;
  margin-top: 16px;
  font-size: 14px;
  font-weight: 600;
  color: var(--orange);
  transition: transform 0.2s ease;
}
.feature:hover .feature__more { transform: translateX(4px); }
.matrix__note {
  text-align: center;
  color: var(--ink-soft);
  font-size: 15px;
  margin-top: 36px;
}

/* ---------- Loop ---------- */
.loop {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  counter-reset: step;
}
.loop__step {
  position: relative;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 40px 30px 34px;
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}
.loop__step:hover { transform: translateY(-6px); box-shadow: var(--shadow); }
.loop__num {
  font-family: var(--font-en);
  font-size: 18px;
  font-weight: 700;
  color: #fff;
  background: var(--orange);
  width: 38px; height: 38px;
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 18px;
}
.loop__step h3 { font-family: var(--font-en); font-size: 21px; font-weight: 600; }
.loop__zh { color: var(--ink); font-weight: 600; margin-top: 2px; }
.loop__text { color: var(--ink-soft); font-size: 15px; margin-top: 12px; }

/* ---------- Model ---------- */
.model {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.model__col {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 34px 30px;
}
.model__col--quote { background: var(--ink); border-color: var(--ink); }
.model__head {
  font-size: 14px;
  letter-spacing: 0.1em;
  color: var(--orange);
  text-transform: uppercase;
  font-weight: 600;
  margin-bottom: 16px;
}
.model__col p { color: var(--ink-soft); font-size: 16px; }
.model__col .accent { font-weight: 600; }
.model__list { list-style: none; }
.model__list li { color: var(--ink-soft); font-size: 16px; padding: 8px 0; border-top: 1px solid var(--line); }
.model__list li:first-child { border-top: none; padding-top: 0; }
.model__list strong { color: var(--ink); }
.model__col--quote .model__head { color: var(--orange-soft); }
.model__question { color: #fff !important; font-size: 17px; font-weight: 500; line-height: 1.7; }

/* ---------- Philosophy ---------- */
.philosophy {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 18px;
}
.philo {
  border-top: 3px solid var(--orange);
  padding-top: 18px;
}
.philo span {
  font-size: 19px;
  font-weight: 700;
  display: block;
  margin-bottom: 10px;
}
.philo p { color: var(--ink-soft); font-size: 14px; }

/* ---------- Result ---------- */
.section--result {
  max-width: none;
  background: var(--ink);
  color: #fff;
}
.section--result > * { max-width: 820px; margin-left: auto; margin-right: auto; text-align: center; }
.result__inner { padding: 130px 28px; }
.eyebrow--light { color: var(--orange-soft); }
.result__title {
  font-size: clamp(36px, 6vw, 64px);
  font-weight: 700;
  margin: 16px 0 28px;
}
.result__lead { font-size: 20px; font-weight: 500; }
.result__text { color: rgba(255,255,255,0.72); font-size: 17px; margin-top: 18px; }
.result__text strong { color: #fff; }
.result__metaphor {
  margin-top: 36px;
  font-family: var(--font-en);
  font-size: clamp(18px, 2.4vw, 24px);
  color: var(--orange-soft);
  line-height: 1.5;
}
.result__ice {
  width: 84px;
  margin: 48px auto 0;
  opacity: 0.92;
  animation: float 5s ease-in-out infinite;
}

/* ---------- Footer ---------- */
.footer {
  background: #0e0e12;
  color: rgba(255,255,255,0.7);
  padding: 72px 28px 36px;
}
.footer__inner {
  max-width: var(--max);
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  gap: 40px;
  flex-wrap: wrap;
  padding-bottom: 40px;
  border-bottom: 1px solid rgba(255,255,255,0.1);
}
.footer__brand { display: flex; flex-direction: column; gap: 14px; }
.footer__logo {
  max-height: 60px;
  width: auto;
  align-self: flex-start;
}
.footer__slogan { font-size: 14px; line-height: 1.6; color: rgba(255, 255, 255, 0.75); }
.footer__links { display: flex; flex-direction: column; gap: 12px; font-size: 15px; }
.footer__links a:hover { color: var(--orange); }
.footer__products { display: flex; flex-direction: column; gap: 12px; font-size: 15px; }
.footer__products a { color: inherit; transition: color 0.2s ease; }
.footer__products a:hover { color: var(--orange); }
.footer__col-title {
  font-size: 13px;
  letter-spacing: 0.14em;
  font-weight: 600;
  color: rgba(255, 255, 255, 0.5);
  margin-bottom: 2px;
}
.footer__bottom {
  max-width: var(--max);
  margin: 28px auto 0;
  display: flex;
  justify-content: space-between;
  gap: 20px;
  flex-wrap: wrap;
  font-size: 13px;
  color: rgba(255,255,255,0.4);
  font-family: var(--font-en);
}

/* ---------- 滚动揭示动画 ---------- */
.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.7s cubic-bezier(0.22, 1, 0.36, 1),
              transform 0.7s cubic-bezier(0.22, 1, 0.36, 1);
}
.reveal.is-visible { opacity: 1; transform: translateY(0); }

@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
  .hero__ice, .result__ice, .hero__scroll span { animation: none; }
}

/* ---------- 响应式 ---------- */
@media (max-width: 920px) {
  .nav__links { display: none; }
  .section__grid { grid-template-columns: 1fr; gap: 36px; }
  .features, .loop, .model { grid-template-columns: 1fr; }
  .philosophy { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 540px) {
  :root { --pad-x: 20px; }
  .section { padding: 80px var(--pad-x); }
  .philosophy { grid-template-columns: 1fr; }
  .nav__cta { display: none; }
  .hero__actions { flex-direction: column; }
}

/* ============================================================
   暗色主题：html[data-theme="dark"]
   深色背景 + 橙色高亮，默认浅色，可一键切换
   ============================================================ */
:root[data-theme="dark"] {
  --bg: #0e0e12;
  --bg-tint: #16161c;
  --ink: #f4f4f7;
  --ink-soft: #a6a6b2;
  --line: #26262e;
  --orange: #ff7a47;
  --orange-soft: #ff9b73;
  --orange-tint: rgba(255, 122, 71, 0.14);
}

:root[data-theme="dark"] .feature,
:root[data-theme="dark"] .loop__step,
:root[data-theme="dark"] .model__col:not(.model__col--quote),
:root[data-theme="dark"] .stat {
  background: #1a1a22;
  border-color: var(--line);
}

:root[data-theme="dark"] .nav.scrolled {
  background: rgba(14, 14, 18, 0.82);
}

:root[data-theme="dark"] .hero__glow {
  background: radial-gradient(circle, rgba(255, 122, 71, 0.12) 0%, rgba(255,122,71,0) 65%);
}

:root[data-theme="dark"] .footer {
  background: #08080b;
}

:root[data-theme="dark"] .section--result {
  background: #16161a;
}