:root {
  --navy: #101b52;
  --blue: #1e3aba;
  --bright: #006bff;
  --orange: #ff6b35;
  --ink: #162033;
  --muted: #667085;
  --line: #e4e9f2;
  --soft: #f5f8fd;
  --paper: #f4eddb;
  --red: #a63a30;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: #fff;
  font-family: Inter, "Noto Sans SC", "PingFang SC", -apple-system, BlinkMacSystemFont, sans-serif;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
.rail { width: min(1180px, calc(100% - 48px)); margin-inline: auto; }
.site-nav {
  position: sticky;
  top: 0;
  z-index: 50;
  border-bottom: 1px solid rgba(228, 233, 242, .9);
  background: rgba(255, 255, 255, .94);
  backdrop-filter: blur(16px);
}
.nav-inner { min-height: 78px; display: flex; align-items: center; justify-content: space-between; gap: 28px; }
.brand { display: flex; align-items: center; gap: 12px; }
.brand img { width: 108px; height: 48px; object-fit: contain; }
.brand-copy strong { display: block; color: var(--navy); letter-spacing: .08em; }
.brand-copy small { color: #7b8495; font-size: 10px; font-weight: 700; }
.nav-links { display: flex; align-items: center; gap: 24px; font-size: 14px; font-weight: 650; }
.nav-links a:hover, .nav-links a[aria-current="page"] { color: var(--bright); }
.nav-button, .primary-button, .secondary-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  min-height: 46px;
  padding: 0 22px;
  border-radius: 999px;
  font-weight: 750;
  transition: transform .2s ease, box-shadow .2s ease, background .2s ease;
}
.nav-button, .primary-button { color: #fff; background: var(--orange); box-shadow: 0 10px 24px rgba(255,107,53,.22); }
.secondary-button { color: var(--navy); background: #fff; border: 1px solid var(--line); }
.nav-button:hover, .primary-button:hover, .secondary-button:hover { transform: translateY(-2px); }
.eyebrow { color: var(--orange); font-size: 12px; font-weight: 850; letter-spacing: .16em; text-transform: uppercase; }
.page-hero { padding: 104px 0 86px; background: radial-gradient(circle at 80% 20%, #e9f1ff 0, transparent 35%), linear-gradient(180deg, #fff, #f7f9fd); }
.page-hero h1 { max-width: 850px; margin: 14px 0 22px; color: var(--navy); font-size: clamp(44px, 7vw, 82px); line-height: 1.05; letter-spacing: -.055em; }
.page-hero p { max-width: 720px; margin: 0; color: var(--muted); font-size: clamp(17px, 2vw, 21px); line-height: 1.75; }
.section { padding: 88px 0; }
.section-soft { background: var(--soft); }
.section-head { display: flex; align-items: end; justify-content: space-between; gap: 32px; margin-bottom: 34px; }
.section-head h2 { margin: 8px 0 0; color: var(--navy); font-size: clamp(32px, 4vw, 50px); letter-spacing: -.04em; }
.section-head p { max-width: 500px; margin: 0; color: var(--muted); line-height: 1.7; }
.case-list { display: grid; gap: 34px; }
.case-card { display: grid; grid-template-columns: 1.08fr .92fr; min-height: 500px; overflow: hidden; border: 1px solid var(--line); border-radius: 28px; background: #fff; box-shadow: 0 24px 70px rgba(16,27,82,.09); }
.case-media { position: relative; min-height: 440px; overflow: hidden; background: var(--paper); }
.case-media img { width: 100%; height: 100%; object-fit: cover; object-position: center; transition: transform .55s ease; }
.case-card:hover .case-media img { transform: scale(1.025); }
.case-badge { position: absolute; left: 22px; top: 22px; padding: 8px 12px; border-radius: 999px; color: #fff; background: rgba(16,27,82,.9); font-size: 12px; font-weight: 800; letter-spacing: .08em; }
.case-copy { padding: clamp(32px, 5vw, 62px); display: flex; flex-direction: column; justify-content: center; }
.case-copy h2 { margin: 12px 0 18px; color: var(--navy); font-size: clamp(34px, 4vw, 54px); line-height: 1.12; letter-spacing: -.04em; }
.case-copy > p { margin: 0; color: var(--muted); font-size: 17px; line-height: 1.75; }
.case-card-swift .case-media { background: #fff; }
.case-card-swift .case-media img { object-fit: contain; padding: 20px; }
.case-card-swift .case-badge { background: rgba(0, 105, 130, .92); }
.case-card-beidou .case-media { background: #eef3ff; }
.case-card-beidou .case-media iframe { width: 100%; height: 100%; min-height: 500px; border: 0; pointer-events: none; }
.case-card-beidou .case-badge { background: #1e3aba; }
.beidou-hero { background: linear-gradient(135deg,#10214a,#244a91); }
.beidou-hero .detail-preview iframe { display: block; width: 100%; height: 470px; border: 0; }
.beidou-hero .eyebrow { color: #ffd166; }
.tags { display: flex; flex-wrap: wrap; gap: 8px; margin: 26px 0 32px; }
.tag { padding: 7px 11px; border-radius: 999px; color: var(--blue); background: #edf3ff; font-size: 12px; font-weight: 750; }
.empty-note { margin-top: 30px; color: #98a2b3; font-size: 13px; text-align: center; }
.site-footer { padding: 44px 0; color: #aeb9d2; background: #10162d; }
.footer-inner { display: flex; justify-content: space-between; gap: 24px; font-size: 13px; }

.detail-hero { padding: 70px 0 82px; background: linear-gradient(135deg, #101b52 0%, #142a78 62%, #1737a2 100%); color: #fff; }
.breadcrumb { margin-bottom: 54px; color: #cbd6f7; font-size: 13px; }
.breadcrumb a:hover { color: #fff; }
.detail-grid { display: grid; grid-template-columns: .82fr 1.18fr; align-items: center; gap: 62px; }
.detail-copy h1 { margin: 16px 0 22px; font-family: "Noto Serif SC", "Songti SC", serif; font-size: clamp(44px, 5.8vw, 72px); line-height: 1.12; letter-spacing: -.045em; }
.detail-copy p { margin: 0; color: #dbe4ff; font-size: 18px; line-height: 1.8; }
.detail-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 32px; }
.detail-preview { overflow: hidden; border: 1px solid rgba(255,255,255,.2); border-radius: 20px; background: var(--paper); box-shadow: 0 28px 70px rgba(2,7,30,.35); transform: rotate(1deg); }
.detail-preview img { aspect-ratio: 1.4; object-fit: cover; object-position: center; }
.stats { display: grid; grid-template-columns: repeat(3,1fr); gap: 16px; margin-top: -38px; position: relative; z-index: 3; }
.stat { padding: 26px; border: 1px solid var(--line); border-radius: 18px; background: #fff; box-shadow: 0 16px 40px rgba(16,27,82,.08); }
.stat strong { display: block; color: var(--navy); font-size: 31px; }
.stat span { color: var(--muted); font-size: 13px; }
.feature-grid { display: grid; grid-template-columns: repeat(3,1fr); gap: 20px; }
.feature { padding: 30px; border: 1px solid var(--line); border-radius: 20px; background: #fff; }
.feature-no { color: var(--orange); font-size: 12px; font-weight: 850; letter-spacing: .12em; }
.feature h3 { margin: 13px 0 10px; color: var(--navy); font-size: 21px; }
.feature p, .boundary p { margin: 0; color: var(--muted); line-height: 1.72; }
.boundary { display: grid; grid-template-columns: .7fr 1.3fr; gap: 48px; padding: 42px; border-radius: 24px; background: #fff8f4; border: 1px solid #ffe0d2; }
.boundary h2 { margin: 8px 0 0; color: #842f27; font-size: 32px; }
.boundary-list { display: grid; gap: 14px; }
.boundary-item { padding-bottom: 14px; border-bottom: 1px solid #f2d7cc; }
.boundary-item:last-child { padding-bottom: 0; border: 0; }
.boundary-item strong { display: block; margin-bottom: 4px; color: #702922; }
.final-cta { padding: 84px 0; color: #fff; text-align: center; background: var(--navy); }
.final-cta h2 { margin: 0 0 16px; font-size: clamp(34px, 4vw, 50px); }
.final-cta p { margin: 0 auto 28px; max-width: 650px; color: #cbd6f7; line-height: 1.7; }

.swift-hero { background: linear-gradient(135deg, #07384b 0%, #075a70 58%, #0d7680 100%); }
.swift-hero .detail-preview { background: #fff; }
.swift-hero .detail-preview img { object-fit: contain; }
.swift-hero .eyebrow { color: #ffd166; }
.swift-hero .primary-button { color: #07384b; background: #ffd166; box-shadow: 0 10px 24px rgba(255,209,102,.22); }
.swift-hero .detail-copy p { color: #d9f1f2; }
.program-switch { display: inline-flex; gap: 6px; padding: 6px; border-radius: 999px; background: #e9eff6; }
.program-switch button { padding: 11px 18px; border: 0; border-radius: 999px; color: #526173; background: transparent; font: inherit; font-size: 14px; font-weight: 800; cursor: pointer; }
.program-switch button.is-active { color: #fff; background: #075a70; box-shadow: 0 6px 16px rgba(7,90,112,.2); }
.program-note { margin: 18px 0 0; color: var(--muted); line-height: 1.7; }
.lesson-grid { display: grid; grid-template-columns: repeat(2,1fr); gap: 20px; margin-top: 34px; }
.lesson-card { position: relative; padding: 30px; overflow: hidden; border: 1px solid var(--line); border-radius: 22px; background: #fff; transition: opacity .2s ease, transform .2s ease; }
.lesson-card[data-extension="true"] { border-color: #cfe5e7; background: #f5fbfb; }
.lesson-card.is-hidden { display: none; }
.lesson-meta { display: flex; justify-content: space-between; gap: 14px; color: #087087; font-size: 12px; font-weight: 850; letter-spacing: .08em; }
.lesson-card h3 { margin: 16px 0 10px; color: var(--navy); font-size: 24px; }
.lesson-card > p { margin: 0 0 20px; color: var(--muted); line-height: 1.7; }
.lesson-steps { display: grid; gap: 10px; padding: 0; margin: 0; list-style: none; }
.lesson-steps li { display: grid; grid-template-columns: 58px 1fr; gap: 12px; color: #344054; font-size: 14px; line-height: 1.55; }
.lesson-steps time { color: #087087; font-weight: 800; }
.mission { display: grid; grid-template-columns: .72fr 1.28fr; gap: 46px; align-items: start; }
.mission h2 { margin: 8px 0 18px; color: var(--navy); font-size: clamp(32px,4vw,48px); line-height: 1.18; }
.mission > div > p { color: var(--muted); line-height: 1.75; }
.mission-chain { display: grid; gap: 13px; }
.mission-step { display: grid; grid-template-columns: 42px 1fr; gap: 16px; padding: 20px; border: 1px solid var(--line); border-radius: 16px; background: #fff; }
.mission-step b { display: grid; place-items: center; width: 42px; height: 42px; border-radius: 50%; color: #fff; background: #087087; }
.mission-step strong { display: block; color: var(--navy); margin-bottom: 5px; }
.mission-step span { color: var(--muted); font-size: 14px; line-height: 1.6; }
.outcome-grid { display: grid; grid-template-columns: repeat(3,1fr); gap: 16px; }
.outcome-card { padding: 24px; border-radius: 18px; color: #16404d; background: #eef9f8; border: 1px solid #d1eae8; }
.outcome-card strong { display: block; margin-bottom: 7px; color: #075a70; font-size: 17px; }
.principle-callout { margin-top: 28px; padding: 24px 28px; border-left: 4px solid #ffd166; color: #243746; background: #fffaf0; font-size: 18px; line-height: 1.7; }
.program-tier-grid { display: grid; grid-template-columns: repeat(3,1fr); gap: 18px; }
.program-tier { padding: 30px; border: 1px solid var(--line); border-radius: 22px; background: #fff; }
.program-tier--featured { color: #fff; background: #075a70; border-color: #075a70; box-shadow: 0 20px 48px rgba(7,90,112,.2); transform: translateY(-8px); }
.program-tier > span { color: #087087; font-size: 11px; font-weight: 850; letter-spacing: .16em; }
.program-tier--featured > span { color: #ffd166; }
.program-tier h3 { margin: 13px 0 9px; color: var(--navy); font-size: 25px; }
.program-tier--featured h3 { color: #fff; }
.program-tier strong { display: block; color: #075a70; font-size: 14px; }
.program-tier--featured strong { color: #ffd166; }
.program-tier p { min-height: 94px; color: var(--muted); line-height: 1.7; }
.program-tier--featured p { color: #d9f1f2; }
.program-tier ul { display: grid; gap: 10px; padding-left: 20px; margin: 22px 0 0; color: #344054; font-size: 14px; line-height: 1.55; }
.program-tier--featured ul { color: #eefafa; }
.international-section { background: #0c2731; color: #fff; }
.international-grid { display: grid; grid-template-columns: 1.1fr .9fr; gap: 60px; align-items: center; }
.international-grid h2 { margin: 10px 0 20px; font-size: clamp(34px,4vw,52px); line-height: 1.15; }
.international-grid p { color: #c7dee2; line-height: 1.8; }
.github-note { display: grid; gap: 8px; margin-top: 28px; padding: 22px; border-left: 4px solid #ffd166; background: rgba(255,255,255,.07); }
.github-note strong { color: #ffd166; }
.github-note span { color: #d6e7e9; font-size: 14px; line-height: 1.75; }
.portfolio-placeholder { padding: 34px; border: 1px solid rgba(255,255,255,.16); border-radius: 24px; background: rgba(255,255,255,.07); box-shadow: 0 22px 60px rgba(0,0,0,.2); }
.portfolio-placeholder > span { color: #77d4cc; font-size: 11px; font-weight: 850; letter-spacing: .15em; }
.portfolio-placeholder h3 { margin: 13px 0 8px; font-size: 26px; }
.portfolio-placeholder small { color: #9fc0c6; font-weight: 700; }
.portfolio-slots { display: grid; grid-template-columns: repeat(2,1fr); gap: 9px; margin: 24px 0 18px; }
.portfolio-slots img { width: 100%; aspect-ratio: 1.2; object-fit: cover; border-radius: 12px; border: 1px solid rgba(255,255,255,.18); background: #70a8e5; }

@media (max-width: 900px) {
  .nav-links a:not(.nav-button) { display: none; }
  .case-card, .detail-grid, .boundary, .mission, .program-tier-grid, .international-grid { grid-template-columns: 1fr; }
  .case-media { min-height: 360px; }
  .detail-preview { transform: none; }
  .stats, .feature-grid, .lesson-grid, .outcome-grid { grid-template-columns: 1fr; }
  .section-head { align-items: start; flex-direction: column; }
  .program-tier--featured { transform: none; }
}
@media (max-width: 560px) {
  .rail { width: min(100% - 28px, 1180px); }
  .nav-inner { min-height: 66px; }
  .brand img { width: 88px; height: 40px; }
  .brand-copy { display: none; }
  .nav-button { min-height: 40px; padding: 0 15px; font-size: 12px; }
  .page-hero { padding: 68px 0 58px; }
  .page-hero h1 { font-size: 43px; }
  .section { padding: 62px 0; }
  .case-media { min-height: 250px; }
  .case-copy { padding: 28px 24px 32px; }
  .detail-hero { padding: 32px 0 60px; }
  .breadcrumb { margin-bottom: 38px; }
  .detail-copy h1 { font-size: 44px; }
  .detail-actions > * { width: 100%; }
  .stats { margin-top: -24px; }
  .boundary { padding: 28px 22px; gap: 26px; }
  .footer-inner { flex-direction: column; }
}