:root {
  --ink: #07172b;
  --navy: #061a35;
  --blue: #1478be;
  --orange: #f29423;
  --paper: #f4f1e9;
  --white: #fff;
  --line: rgba(7, 23, 43, .16);
  --nav-height: 76px;
  color-scheme: light;
  font-family: "Noto Sans SC", "Microsoft YaHei UI", "PingFang SC", sans-serif;
  font-synthesis: none;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; color: var(--ink); background: var(--paper); }
button, input { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
a { color: inherit; }

.site-nav {
  position: absolute;
  inset: 0 0 auto;
  z-index: 20;
  height: var(--nav-height);
  padding: 0 clamp(22px, 4.5vw, 72px);
  display: flex;
  align-items: center;
  justify-content: space-between;
  color: var(--white);
  border-bottom: 1px solid rgba(255,255,255,.16);
}
.site-nav--solid { position: fixed; background: rgba(6, 26, 53, .96); backdrop-filter: blur(16px); }
.nav-brand { display: inline-flex; align-items: center; width: 156px; height: 48px; overflow: hidden; }
.nav-brand img { width: 100%; height: auto; display: block; }
.nav-actions { display: flex; align-items: center; gap: clamp(16px, 2.7vw, 42px); }
.nav-link {
  position: relative;
  appearance: none;
  border: 0;
  padding: 8px 0;
  background: none;
  color: inherit;
  text-decoration: none;
  cursor: pointer;
  font-size: 14px;
}
.nav-link::after { content: ""; position: absolute; left: 0; right: 100%; bottom: 1px; height: 1px; background: var(--orange); transition: right .25s ease; }
.nav-link:hover::after, .nav-link.active::after { right: 0; }
.nav-user { display: inline-flex; align-items: center; gap: 10px; }
.nav-user > span:first-child { max-width: min(24vw, 260px); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.points-chip { color: #ffd5a1; }

.brand-hero {
  position: relative;
  min-height: 100svh;
  overflow: hidden;
  display: grid;
  align-items: center;
  color: var(--white);
  background: var(--navy);
}
.hero-image { position: absolute; inset: 0; background: url("/platform/assets/beiduofen-brand-hero.png") center / cover no-repeat; animation: hero-depth 10s ease-out both; }
.hero-shade { position: absolute; inset: 0; background: linear-gradient(90deg, rgba(3,15,32,.86) 0%, rgba(3,15,32,.57) 42%, rgba(3,15,32,.04) 72%), linear-gradient(180deg, rgba(3,15,32,.14), rgba(3,15,32,.34)); }
.hero-content { position: relative; z-index: 2; width: min(660px, 80vw); margin-left: clamp(24px, 8vw, 132px); padding-top: var(--nav-height); }
.hero-kicker, .section-index, .modal-kicker { margin: 0; font-size: 11px; line-height: 1.4; letter-spacing: .24em; text-transform: uppercase; }
.hero-kicker { color: #f6bd73; animation: rise-in .7s .12s both; }
.hero-logo { display: block; width: clamp(190px, 22vw, 320px); margin: 18px 0 24px; animation: rise-in .8s .2s both; }
.hero-content h1 { margin: 0; font-size: clamp(42px, 5.1vw, 78px); line-height: 1.1; letter-spacing: -.045em; font-weight: 700; animation: rise-in .85s .28s both; }
.hero-lead { max-width: 560px; margin: 26px 0 0; color: rgba(255,255,255,.72); font-size: clamp(15px, 1.2vw, 18px); line-height: 1.9; animation: rise-in .85s .37s both; }
.hero-actions { display: flex; align-items: center; gap: 24px; margin-top: 36px; animation: rise-in .85s .46s both; }
.primary-action, .form-submit {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 28px;
  min-height: 52px;
  border: 1px solid var(--orange);
  padding: 0 24px;
  background: var(--orange);
  color: #101927;
  text-decoration: none;
  font-weight: 700;
  cursor: pointer;
  transition: background .25s ease, color .25s ease, transform .25s ease;
}
.primary-action:hover, .form-submit:hover { background: #ffab43; transform: translateY(-2px); }
.secondary-action { color: rgba(255,255,255,.84); font-size: 14px; text-underline-offset: 6px; }
.scroll-cue { position: absolute; z-index: 3; right: clamp(24px, 4.5vw, 72px); bottom: 32px; display: flex; align-items: center; gap: 16px; color: rgba(255,255,255,.58); text-decoration: none; font-size: 11px; letter-spacing: .12em; }
.scroll-cue i { display: block; width: 50px; height: 1px; background: rgba(255,255,255,.5); transform-origin: left; animation: cue 2s ease-in-out infinite; }

.tools-section { padding: clamp(64px, 7vw, 104px) clamp(24px, 7vw, 112px); background: var(--paper); }
.section-index { align-self: start; color: #4d6580; }
.tool-matrix { display: grid; grid-template-columns: 1fr 1fr; border-top: 1px solid var(--line); border-left: 1px solid var(--line); }
.tool-entry { min-height: 330px; padding: clamp(28px, 3.4vw, 52px); display: grid; grid-template-columns: 44px 1fr; grid-template-rows: 1fr auto; column-gap: 28px; border-right: 1px solid var(--line); border-bottom: 1px solid var(--line); color: inherit; text-decoration: none; background: transparent; transition: background .35s ease, color .35s ease; }
.tool-entry:hover { background: var(--navy); color: var(--white); }
.tool-number { color: var(--orange); font-size: 12px; }
.tool-domain { margin: 0 0 14px; color: #55718d; font-size: 12px; letter-spacing: .12em; }
.tool-entry:hover .tool-domain { color: #89aac8; }
.tool-entry h3 { margin: 0; font-size: clamp(27px, 2.7vw, 42px); letter-spacing: -.035em; }
.tool-entry div > p:last-child { max-width: 420px; margin: 20px 0 0; color: #5b6877; line-height: 1.8; }
.tool-entry:hover div > p:last-child { color: rgba(255,255,255,.62); }
.tool-entry footer { grid-column: 2; display: flex; align-items: center; justify-content: space-between; margin-top: 36px; color: #5a6b7c; font-size: 13px; }
.tool-entry footer b { color: var(--orange); font-size: 24px; transform: translate(0, 0); transition: transform .25s ease; }
.tool-entry:hover footer { color: rgba(255,255,255,.7); }
.tool-entry:hover footer b { transform: translate(5px, -5px); }

.site-footer { min-height: 180px; padding: 46px clamp(24px, 7vw, 112px); display: grid; grid-template-columns: 1fr auto auto; gap: 36px; align-items: end; background: #04152b; color: rgba(255,255,255,.52); font-size: 12px; }
.site-footer img { width: 150px; }
.site-footer p { margin: 0; }

.about-page { background: #f1eee6; }
.about-main { padding-top: var(--nav-height); }
.about-intro { min-height: 72svh; padding: clamp(100px, 13vw, 190px) clamp(24px, 9vw, 150px) 80px; display: grid; grid-template-columns: .35fr 1.45fr .55fr; gap: 50px; align-items: start; background: #09213e; color: var(--white); }
.about-intro .section-index { color: #8fa9c6; }
.about-intro h1 { margin: 0; font-size: clamp(48px, 5vw, 78px); line-height: 1.08; letter-spacing: -.055em; }
.about-intro h1 span { display: block; white-space: nowrap; }
.about-intro > p:last-child { margin: 12px 0 0; color: rgba(255,255,255,.62); line-height: 1.9; }
.about-story { padding: clamp(90px, 11vw, 170px) clamp(24px, 9vw, 150px); display: grid; grid-template-columns: .55fr 1.45fr; gap: clamp(60px, 10vw, 160px); }
.about-story aside { display: flex; flex-direction: column; gap: 18px; color: #66798d; font-size: 13px; }
.story-copy p { margin: 0 0 45px; font-family: "Songti SC", SimSun, serif; font-size: clamp(22px, 2.2vw, 34px); line-height: 1.75; letter-spacing: -.02em; }
.about-principles { padding: 100px clamp(24px, 9vw, 150px) 140px; background: #fff; }
.about-principles > div { margin-top: 50px; display: grid; grid-template-columns: repeat(3, 1fr); border-left: 1px solid var(--line); }
.about-principles article { padding: 20px 44px 40px; border-right: 1px solid var(--line); }
.about-principles article span { color: var(--orange); font-size: 12px; }
.about-principles h2 { margin: 54px 0 18px; font-size: 32px; }
.about-principles article p { margin: 0; color: #59697a; line-height: 1.8; }

.modal { width: min(480px, calc(100vw - 32px)); border: 0; padding: 44px; color: var(--ink); background: #faf8f2; box-shadow: 0 30px 100px rgba(0,0,0,.35); }
.modal::backdrop { background: rgba(2, 14, 30, .74); backdrop-filter: blur(6px); }
.modal-close { position: absolute; top: 15px; right: 18px; border: 0; background: transparent; color: #6c7783; font-size: 30px; cursor: pointer; }
.modal-kicker { color: #657a8f; }
.modal h2 { margin: 16px 0 22px; font-size: 29px; line-height: 1.3; letter-spacing: -.03em; }
.modal-description { color: #5b6876; line-height: 1.7; }
.auth-tabs { display: grid; grid-template-columns: 1fr 1fr; margin: 8px 0 24px; border-bottom: 1px solid var(--line); }
.auth-tabs button { border: 0; border-bottom: 2px solid transparent; padding: 12px; background: transparent; color: #75808a; cursor: pointer; }
.auth-tabs button.active { border-color: var(--orange); color: var(--ink); font-weight: 700; }
.modal form { display: grid; gap: 18px; }
.modal label { display: grid; gap: 8px; color: #33465a; font-size: 13px; }
.modal input { width: 100%; height: 50px; border: 1px solid #c8c9c4; padding: 0 14px; outline: none; background: #fff; }
.modal input:focus { border-color: var(--blue); box-shadow: 0 0 0 3px rgba(20,120,190,.12); }
.form-message { min-height: 20px; margin: -5px 0 0; color: #b33528; font-size: 13px; }
.form-message.success { color: #17704e; }
.form-submit { width: 100%; }
.purchase-link { margin-top: 18px; min-height: 48px; display: flex; align-items: center; justify-content: center; gap: 20px; border: 1px solid var(--ink); text-decoration: none; font-weight: 700; }

.reveal { opacity: 0; transform: translateY(28px); transition: opacity .7s ease, transform .7s cubic-bezier(.2,.7,.2,1); }
.reveal.is-visible { opacity: 1; transform: translateY(0); }
@keyframes rise-in { from { opacity: 0; transform: translateY(24px); } to { opacity: 1; transform: none; } }
@keyframes hero-depth { from { transform: scale(1.045); } to { transform: scale(1); } }
@keyframes cue { 0%,100% { transform: scaleX(.45); opacity: .35; } 50% { transform: scaleX(1); opacity: 1; } }

@media (max-width: 900px) {
  :root { --nav-height: 68px; }
  .site-nav { padding: 0 20px; }
  .nav-brand { width: 126px; }
  .nav-actions { gap: 14px; }
  .nav-link { font-size: 12px; }
  .hero-content { width: auto; margin: 0 24px; }
  .hero-shade { background: linear-gradient(90deg, rgba(3,15,32,.9), rgba(3,15,32,.38)), linear-gradient(180deg, transparent, rgba(3,15,32,.4)); }
  .tool-matrix { grid-template-columns: 1fr; }
  .about-intro { grid-template-columns: 1fr; min-height: auto; }
  .about-story { grid-template-columns: 1fr; }
  .about-principles > div { grid-template-columns: 1fr; border-top: 1px solid var(--line); }
  .about-principles article { border-bottom: 1px solid var(--line); }
}
@media (max-width: 620px) {
  .nav-actions .nav-link:nth-child(2) { display: none; }
  .nav-user > span:first-child { max-width: 94px; }
  .nav-user .points-chip { display: none; }
  .hero-image { background-position: 62% center; }
  .hero-logo { width: 210px; }
  .hero-actions { align-items: flex-start; flex-direction: column; gap: 18px; }
  .scroll-cue { display: none; }
  .tool-entry { min-height: 290px; grid-template-columns: 30px 1fr; column-gap: 15px; }
  .about-intro h1 { font-size: clamp(32px, 10.2vw, 42px); }
  .site-footer { grid-template-columns: 1fr; align-items: start; }
  .modal { padding: 38px 24px 28px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; }
  .reveal { opacity: 1; transform: none; }
}