:root{--ink:#172e49;--muted:#637386;--blue:#2158cd;--green:#187a65;--line:#dfe6ed;--paper:#f6f8fa}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:30px}body{margin:0;background:var(--paper);color:var(--ink);font:15px/1.7 -apple-system,BlinkMacSystemFont,"Segoe UI","Noto Sans CJK SC","Microsoft YaHei",sans-serif}a{color:inherit;text-decoration:none}button,input{font:inherit}button,a,input{-webkit-tap-highlight-color:transparent}a:focus-visible,button:focus-visible,input:focus-visible{outline:3px solid #2b62d6;outline-offset:5px}[hidden]{display:none!important}.skip-link{position:absolute;top:-80px;left:20px;padding:12px;background:white;z-index:2}.skip-link:focus{top:8px}.site-header{background:#fff;border-bottom:1px solid var(--line)}.header-inner{max-width:1200px;margin:auto;min-height:88px;display:flex;justify-content:space-between;align-items:center;padding:16px 24px}.brand{display:flex;align-items:center;gap:13px;font-size:19px;font-weight:750;letter-spacing:.4px}.brand small{display:block;color:var(--muted);font-size:10px;letter-spacing:1px;font-weight:500}.brand-mark{width:43px;height:43px;display:flex;flex-direction:column;justify-content:center;align-items:center;gap:3px;background:var(--ink);border-radius:11px}.brand-mark i{width:21px;height:7px;border:1.5px solid #8ad8c5;transform:skewY(-15deg)}nav{display:flex;gap:32px;font-size:13px;font-weight:600}nav a{padding:8px 0}.nav-current{color:var(--blue)}nav a:hover{color:var(--blue)}main{max-width:1200px;margin:auto;padding:0 24px}.hero{display:grid;grid-template-columns:1.08fr 1fr;gap:70px;align-items:center;padding:68px 0 65px}.eyebrow{font-size:10px;letter-spacing:2.2px;font-weight:700;color:var(--muted);display:flex;align-items:center;gap:10px;margin:0 0 20px}.eyebrow>span{width:7px;height:7px;border-radius:100%;background:var(--green)}h1{font-size:60px;line-height:1.28;letter-spacing:-2px;margin:0;font-weight:800}h1 em{color:var(--blue);font-style:normal}.hero-description{font-size:15px;line-height:1.9;color:var(--muted);margin:24px 0 25px}.primary-link{display:inline-flex;align-items:center;gap:34px;background:var(--blue);color:white;border-radius:7px;padding:13px 20px;font-size:14px;font-weight:600;box-shadow:0 6px 14px #2158cd16;transition:background .15s}.primary-link:hover{background:#1447b4}.hero-note{font-size:11px;color:var(--muted);letter-spacing:1px;margin-top:18px}.journey{background:#fff;border:1px solid var(--line);border-radius:14px;padding:22px 24px;box-shadow:0 14px 32px #172e4906;transform:rotate(-1deg)}.diagram-top{display:flex;justify-content:space-between;align-items:center;font-size:12px;font-weight:600;padding-bottom:16px}.diagram-tag{font-size:9px;letter-spacing:1px;color:var(--muted)}.diagram-body{display:flex;gap:16px;background-image:radial-gradient(#d4dee6 1px,transparent 1px);background-size:14px 14px;padding:10px 0}.layer-stack{flex:1;display:grid;gap:6px}.layer{display:flex;align-items:center;gap:17px;padding:6px 14px;border-radius:5px;border:1px solid #d7e5fa;background:#edf4ff;font-size:12px;color:#2e5a94}.layer b{font-size:10px;font-family:ui-monospace,monospace;opacity:.7}.layer span{font-weight:650}.layer small{margin-left:auto;font-size:10px;opacity:.75}.layer.transport{background:#f0ecfb;border-color:#e1d9f2;color:#7256a0}.layer.network{background:#fef4dc;border-color:#f0e3bd;color:#8c6a27}.layer.link{background:#e7f4ee;border-color:#d0e8dc;color:#32735c}.layer.physical{background:#edf1f5;border-color:#dae2e9;color:#52697b}.direction{display:flex;flex-direction:column;align-items:center;width:26px;color:#72869b;font-size:10px}.direction span{writing-mode:vertical-rl;letter-spacing:4px;margin:10px 0}.direction i{height:100%;width:1px;background:#bbcbd9}.direction b{font-size:22px;line-height:1;margin-top:-10px}.diagram-bottom{display:flex;align-items:center;justify-content:space-between;gap:10px;padding-top:17px;margin-top:8px;border-top:1px solid var(--line);font-size:10px;color:var(--muted)}.diagram-bottom i{height:1px;background:var(--line);flex:1}.endpoint{background:#eaf1ff;color:var(--blue);width:25px;height:25px;display:grid;place-items:center;font-weight:700;border-radius:6px}.destination{color:var(--green);background:#e5f4ee}.catalog{border-top:1px solid var(--line);padding-top:39px}.section-heading{display:flex;justify-content:space-between;align-items:end;gap:20px}.section-heading .eyebrow{margin-bottom:10px;font-size:9px}.section-heading h2{margin:0;font-size:25px;letter-spacing:-.6px}.section-heading>p{font-size:11px;color:var(--muted);white-space:nowrap;margin:0 0 4px}.available-dot{display:inline-block;background:var(--green);width:6px;height:6px;border-radius:50%;margin-right:6px}.count-divider{margin:0 10px;color:#b4c0ca}.catalog-tools{display:flex;justify-content:space-between;gap:16px;align-items:center;margin:26px 0 24px}.filters{display:flex;gap:7px;flex-wrap:wrap}.filters button{border:1px solid transparent;background:transparent;color:var(--muted);padding:6px 14px;border-radius:6px;font-size:12px;cursor:pointer}.filters button[aria-pressed=true]{background:#fff;border-color:var(--line);color:var(--ink);font-weight:650;box-shadow:0 2px 3px #172e4905}.search{display:flex;align-items:center;gap:8px;border:1px solid var(--line);background:#fff;border-radius:6px;padding:5px 12px}.search>span{font-size:22px;line-height:1;color:var(--muted)}.search input{width:150px;min-width:0;border:0;outline-offset:0;color:var(--ink);font-size:11px;background:transparent;padding:4px 0}.course-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:17px;margin-top:24px}.course-card{background:#fff;border:1px solid var(--line);border-radius:10px;padding:23px;display:flex;flex-direction:column;min-height:260px;position:relative}.course-card.published{border-color:#9bb6eb;box-shadow:0 3px 12px #2158cd06;transition:transform .15s,box-shadow .15s}.course-card.published:hover{transform:translateY(-3px);box-shadow:0 9px 20px #2158cd10}.course-top{display:flex;justify-content:space-between;align-items:center;margin-bottom:22px}.course-number{font:15px ui-monospace,monospace;color:#9aa9b7}.course-status{font-size:10px;padding:2px 8px;border-radius:4px;background:#f1f4f6;color:#718194}.published .course-status{background:#e7f5ef;color:#187a65}.course-english{font-size:9px;letter-spacing:1.2px;color:var(--muted);margin:0 0 5px}.course-card h3{font-size:20px;margin:0 0 11px;letter-spacing:-.3px}.course-title-link:after{content:"";position:absolute;inset:0;border-radius:10px}.course-description{font-size:12px;line-height:1.9;color:var(--muted);margin:0 0 24px;flex:1}.course-bottom{display:flex;justify-content:space-between;align-items:center;gap:8px;border-top:1px solid #edf0f4;padding-top:14px}.course-tags{display:flex;gap:8px;flex-wrap:wrap;font-size:10px;color:#718194}.course-tags span+span:before{content:"·";margin-right:8px;color:#b9c3ce}.course-arrow{color:var(--blue);font-size:21px;line-height:1}.empty-state{text-align:center;padding:40px;color:var(--muted);font-size:14px}.catalog-note{display:flex;align-items:center;gap:10px;color:var(--muted);margin:25px 0 46px;font-size:11px}.catalog-note>span:first-child{font-size:20px;color:#8d9faf}.catalog-note p{margin:0}.site-address{margin-left:auto;font:10px ui-monospace,monospace;white-space:nowrap;opacity:.8}.teaching-note{display:grid;grid-template-columns:1fr auto;gap:12px 30px;padding:29px 32px 32px;border-radius:10px;background:#eaf0f5;margin-bottom:50px}.note-index{grid-column:1/-1;color:#6d8398;font-size:9px;letter-spacing:2px}.teaching-note h2{margin:0;font-size:22px;grid-column:1}.teaching-note p{margin:0;color:var(--muted);font-size:12px;grid-column:1}.teaching-note a{grid-column:2;grid-row:2/4;align-self:center;font-size:12px;color:var(--blue);border-bottom:1px solid #a0b6da;padding-bottom:4px}.teaching-note a span{padding-left:18px}footer{max-width:1152px;margin:0 auto;padding:22px 0 28px;border-top:1px solid var(--line);display:flex;gap:20px;align-items:center;color:var(--muted);font-size:10px}footer .footer-brand{font-size:12px;color:var(--ink);font-weight:650}footer span:last-child{margin-left:auto}.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip-path:inset(50%);white-space:nowrap}@media(min-width:1500px){.hero{padding:84px 0 78px}}@media(max-width:1000px){.hero{gap:32px}h1{font-size:50px}.journey{padding:18px}.course-grid{grid-template-columns:repeat(2,minmax(0,1fr))}footer{margin:0 24px}.hero-description{font-size:14px}}@media(max-width:700px){main{padding:0 20px}.header-inner{padding:14px 20px;min-height:76px}.brand{font-size:16px;gap:10px}.brand small{font-size:9px}.brand-mark{width:37px;height:37px}nav{gap:16px;font-size:11px}nav a:first-child{display:none}.hero{grid-template-columns:1fr;gap:30px;padding:40px 0 38px}h1{font-size:48px}.hero-description{font-size:13px}.hero-note{font-size:10px}.journey{transform:none;max-width:500px;width:100%}.diagram-body{padding:7px 0}.layer{padding:5px 14px}.catalog{padding-top:28px}.section-heading{align-items:start;flex-direction:column;gap:12px}.section-heading h2{font-size:23px}.catalog-tools{align-items:stretch;flex-direction:column;gap:15px;margin-bottom:20px}.filters{gap:4px}.filters button{padding:6px 10px;font-size:11px}.search input{width:100%;font-size:12px}.search{padding:8px 12px}.course-grid{grid-template-columns:1fr;gap:14px}.course-card{min-height:238px;padding:22px}.course-top{margin-bottom:18px}.course-card h3{font-size:21px}.course-description{font-size:13px}.course-tags{font-size:11px}.catalog-note{align-items:start;margin-bottom:32px}.catalog-note>span:first-child{line-height:1.3}.site-address{display:none}.teaching-note{grid-template-columns:1fr;padding:25px;gap:10px;margin-bottom:32px}.teaching-note h2{font-size:20px}.teaching-note a{grid-column:1;grid-row:auto;justify-self:start;margin-top:8px}.desktop-break{display:none}footer{margin:0 20px;flex-wrap:wrap;gap:8px 15px}footer span:last-child{margin:0;width:100%}}@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*{transition:none!important}}
