:root{--page-bg: #f7f9fb;--surface: #ffffff;--surface-soft: #eef9f6;--text-main: #111827;--text-secondary: #4b5563;--text-muted: #8a94a3;--primary: #0f9f8f;--primary-hover: #087c70;--info: #2563eb;--warning: #f59e0b;--danger: #dc2626;--success: #16a34a;--border: #e5e7eb;--shadow: 0 18px 44px rgba(15, 23, 42, .06);--radius-card: 8px;--radius-button: 6px;--content-max: 1200px;color:var(--text-main);background:var(--page-bg);font-family:Inter,PingFang SC,Hiragino Sans GB,Microsoft YaHei,Arial,sans-serif;font-synthesis:none;text-rendering:optimizeLegibility;-webkit-font-smoothing:antialiased}*{box-sizing:border-box}html,body,#root{min-width:320px;min-height:100%}body{margin:0;background:var(--page-bg)}button,input{font:inherit}button{color:inherit}.web-shell{min-height:100vh}.site-header{position:sticky;top:0;z-index:40;display:flex;align-items:center;justify-content:space-between;min-height:64px;padding:0 clamp(16px,4vw,48px);border-bottom:1px solid rgba(229,231,235,.78);background:#f7f9fbf0;-webkit-backdrop-filter:blur(14px);backdrop-filter:blur(14px)}.brand,.desktop-nav button,.mobile-nav button,.link-panel button,.policy-links button{border:0;background:transparent;cursor:pointer}.brand{display:inline-flex;align-items:center;gap:10px;min-width:168px;font-weight:700}.brand-dot{width:14px;height:14px;border-radius:999px;background:var(--primary)}.desktop-nav{display:flex;align-items:center;gap:8px}.desktop-nav button{min-height:36px;padding:0 12px;border-radius:var(--radius-button);color:var(--text-secondary);font-size:14px}.desktop-nav button:hover,.link-panel button:hover,.policy-links button:hover{background:#eaf5f2;color:var(--primary-hover)}.account-status{max-width:180px;overflow:hidden;padding:7px 12px;border:1px solid #d7eee9;border-radius:999px;color:var(--primary-hover);font-size:13px;text-overflow:ellipsis;white-space:nowrap}main{width:min(var(--content-max),calc(100% - 40px));margin:0 auto;padding:28px 0 88px}.mobile-nav{position:fixed;right:0;bottom:0;left:0;z-index:50;display:none;grid-template-columns:repeat(4,1fr);border-top:1px solid var(--border);background:#fffffff5;-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px)}.mobile-nav button{min-height:56px;color:var(--text-secondary);font-size:13px}.page-section,.profile-page,.payment-page{display:grid;gap:20px}.page-title{display:flex;align-items:flex-end;justify-content:space-between;gap:20px}.page-title h1,.home-copy h1,.payment-card h1,.auth-card h1,.success-card h1{margin:0;color:var(--text-main);font-size:clamp(30px,4.6vw,48px);line-height:1.1;letter-spacing:0}.page-title h1{font-size:clamp(28px,4vw,42px)}.page-title p,.home-copy p,.payment-card p,.auth-card p,.success-card p,.card p,.empty-state p{color:var(--text-secondary);line-height:1.72}.page-title-action,.actions{display:flex;flex-wrap:wrap;gap:10px;align-items:center}.actions.vertical{display:grid}.eyebrow{margin:0 0 8px;color:var(--primary);font-size:12px;font-weight:800;letter-spacing:0}.home-hero{display:grid;grid-template-columns:minmax(0,1fr) 400px;gap:48px;align-items:center;padding:40px 0 36px}.home-hero>*,.detail-hero>*,.detail-layout>*,.redeem-layout>*,.learning-page>*,.profile-grid>*,.course-card,.card,.course-action-panel,.detail-cover-panel{min-width:0}.home-copy{display:grid;gap:18px}.home-copy p{max-width:640px;margin:0;font-size:17px}.hero-course-card,.course-card,.card,.course-action-panel,.empty-state,.auth-card,.success-card,.payment-card,.my-course-card,.identity-card,.lesson-sidebar,.service-card{border:1px solid var(--border);border-radius:var(--radius-card);background:var(--surface);box-shadow:var(--shadow)}.hero-course-card{display:grid;gap:14px;padding:22px}.hero-course-card h2,.course-card h2,.card h2,.course-action-panel h2,.my-course-card h2,.identity-card h2,.lesson-sidebar h2,.service-card h2{margin:0;color:var(--text-main);font-size:22px;line-height:1.28;letter-spacing:0}.hero-metrics,.quick-strip,.course-meta{display:flex;flex-wrap:wrap;gap:10px;align-items:center}.hero-metrics div,.quick-strip div,.course-meta span{border-radius:var(--radius-button);background:var(--surface)}.hero-metrics div{min-width:110px;padding:12px 14px;border:1px solid var(--border)}.hero-metrics strong,.hero-metrics span,.quick-strip span,.quick-strip strong{display:block}.hero-metrics strong{color:var(--primary);font-size:22px}.hero-metrics span,.quick-strip span{color:var(--text-muted);font-size:12px}.quick-strip{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;margin-bottom:14px}.quick-strip div{padding:16px 18px;border:1px solid var(--border)}.quick-strip strong{margin-top:4px;color:var(--primary);font-size:20px}.course-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px}.course-card{overflow:hidden}.course-card-body,.card,.empty-state,.my-course-card,.identity-card,.lesson-sidebar,.service-card{padding:20px}.course-card-body{display:grid;gap:12px}.course-card p,.hero-course-card p{margin:0;color:var(--text-secondary);line-height:1.65}.course-meta span{padding:6px 9px;border:1px solid #dce8e6;color:var(--text-secondary);font-size:13px;line-height:1.2}.cover-art{display:block;width:100%;aspect-ratio:16 / 9;border-radius:var(--radius-card);object-fit:cover}.cover-art.large{min-height:212px}.cover-art-fallback{position:relative;display:grid;align-content:center;gap:16px;padding:28px;overflow:hidden;background:#dff5f0;color:#0f172a}.cover-art-fallback span{position:relative;z-index:1;max-width:90%;overflow-wrap:anywhere;font-weight:700}.cover-chip{position:relative;z-index:1;width:min(230px,82%);padding:11px 14px;border-radius:5px;background:#111827;color:#fff;font-size:12px;letter-spacing:0}.cover-dots{position:absolute;right:22px;bottom:22px;display:flex;gap:6px}.cover-dots i{display:block;width:12px;height:12px;border-radius:999px}.cover-dots i:nth-child(1){background:var(--primary)}.cover-dots i:nth-child(2){background:var(--info)}.cover-dots i:nth-child(3){background:var(--warning)}.btn{display:inline-flex;align-items:center;justify-content:center;min-height:40px;padding:0 16px;border:1px solid var(--border);border-radius:var(--radius-button);background:var(--surface);color:var(--text-main);font-weight:700;line-height:1.2;text-align:center;cursor:pointer}.btn.primary{border-color:var(--primary);background:var(--primary);color:#fff}.btn.primary:hover{border-color:var(--primary-hover);background:var(--primary-hover)}.btn.text{border-color:transparent;background:transparent;color:var(--primary-hover)}.btn.full{width:100%}.btn:disabled{cursor:not-allowed;opacity:.64}.badge{display:inline-flex;width:fit-content;min-height:26px;align-items:center;padding:3px 9px;border-radius:999px;font-size:12px;font-weight:800}.badge.neutral{background:#eef2f7;color:var(--text-secondary)}.badge.success{background:#e8f8f0;color:var(--success)}.badge.warning{background:#fff6df;color:#a16207}.badge.danger{background:#feecec;color:var(--danger)}.detail-hero{display:grid;grid-template-columns:minmax(0,1fr) 340px;gap:26px;align-items:start;margin-bottom:28px}.detail-cover-panel{padding:22px;border-radius:var(--radius-card);background:#e8f7f3}.course-action-panel{position:sticky;top:86px;display:grid;gap:14px;padding:20px}.price-line{color:var(--text-main);font-size:30px;font-weight:800}.compact-facts,.status-list{display:grid;gap:10px;margin:0}.compact-facts div,.status-list div{display:flex;justify-content:space-between;gap:14px;padding:9px 0;border-bottom:1px solid var(--border)}.compact-facts dt,.status-list dt{color:var(--text-muted)}.compact-facts dd,.status-list dd{margin:0;color:var(--text-main);text-align:right}.fine-print,.muted{color:var(--text-muted);font-size:13px;line-height:1.65}.detail-layout{display:grid;grid-template-columns:minmax(0,1fr) 340px;gap:26px}.detail-main{display:grid;gap:18px;grid-column:1 / 2}.value-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}.value-grid div{display:grid;gap:6px;padding:18px;border:1px solid var(--border);border-radius:var(--radius-card);background:var(--surface)}.value-grid strong{color:var(--text-main)}.value-grid span{color:var(--text-secondary);line-height:1.6}.lesson-rows,.materials-list,.link-panel{display:grid;gap:10px}.lesson-rows div,.lesson-rows button,.materials-list button,.link-panel button{display:grid;width:100%;min-height:48px;align-items:center;gap:10px;padding:10px 12px;border:1px solid var(--border);border-radius:var(--radius-button);background:#fbfdfe;text-align:left}.lesson-rows div,.lesson-rows button{grid-template-columns:42px minmax(0,1fr) auto}.lesson-rows button,.materials-list button,.link-panel button{cursor:pointer}.lesson-rows button.active{border-color:#c8ede7;background:#e8f8f5}.lesson-rows span,.lesson-rows small,.materials-list span,.materials-list small{color:var(--text-muted);font-size:12px}.lesson-rows strong,.materials-list strong{min-width:0;overflow-wrap:anywhere}.check-list{display:grid;gap:10px;margin:0;padding-left:20px;color:var(--text-secondary);line-height:1.7}.policy-links{display:flex;flex-wrap:wrap;gap:10px}.policy-links button{min-height:38px;padding:0 12px;border:1px solid var(--border);border-radius:var(--radius-button);background:var(--surface)}.auth-state-page,.redeem-success-page,.payment-page{display:grid;min-height:calc(100vh - 180px);place-items:center}.auth-card,.success-card,.payment-card{display:grid;width:min(440px,100%);gap:16px;padding:34px;text-align:center}.wechat-mark,.success-ring,.empty-icon,.avatar-placeholder{display:grid;place-items:center;margin:0 auto;border-radius:999px}.wechat-mark{width:68px;height:68px;border:2px solid #7bbdf4;color:#2563eb;font-size:24px;font-weight:800}.success-ring{width:74px;height:74px;border:3px solid var(--success)}.success-ring:before{content:"";width:20px;height:34px;border-right:3px solid var(--success);border-bottom:3px solid var(--success);transform:rotate(42deg) translate(-2px,-4px)}.empty-icon,.avatar-placeholder{width:42px;height:42px;border:1px solid var(--primary);background:#e8f8f5}.notice{margin:0;padding:12px;border-radius:var(--radius-card);line-height:1.6;text-align:left}.notice.warning{border:1px solid #f5d998;background:#fff8e7;color:#8a5a02}.notice.danger{border:1px solid #f2b8b8;background:#fff1f1;color:var(--danger)}.redeem-layout{display:grid;grid-template-columns:minmax(0,1fr) 380px;gap:24px;align-items:start}.redeem-form{position:sticky;top:86px;display:grid;gap:14px}.field{display:grid;gap:8px;text-align:left}.field span{color:var(--text-secondary);font-weight:700}.field input{width:100%;min-height:44px;padding:0 12px;border:1px solid var(--border);border-radius:var(--radius-button);background:#fff;color:var(--text-main)}.my-course-list{display:grid;gap:18px}.identity-card,.my-course-card{display:grid;grid-template-columns:120px minmax(0,1fr) auto;gap:18px;align-items:center}.identity-card{grid-template-columns:48px minmax(0,1fr) auto}.my-course-card .cover-art{min-width:0}.my-course-content{display:grid;gap:10px}.course-card-actions{display:grid;min-width:120px;gap:10px}.progress-track{height:8px;overflow:hidden;border-radius:999px;background:#e5e7eb}.progress-track span{display:block;height:100%;border-radius:inherit;background:var(--primary)}.learning-page{display:grid;grid-template-columns:minmax(760px,1fr) 300px;gap:24px;align-items:start}.learning-main{display:grid;gap:16px}.player-frame,.video-player,.player-placeholder{width:100%;aspect-ratio:16 / 9;border-radius:var(--radius-card);background:#111827}.video-player{display:block}.player-placeholder{display:grid;place-items:center;gap:12px;padding:24px;color:#fff;text-align:center}.play-mark{width:0;height:0;border-top:24px solid transparent;border-bottom:24px solid transparent;border-left:36px solid var(--primary)}.lesson-sidebar{position:sticky;top:86px;display:grid;gap:14px}.materials-list button{grid-template-columns:82px minmax(0,1fr) 42px}.profile-grid{display:grid;grid-template-columns:320px minmax(0,1fr);gap:20px}.profile-card{display:grid;gap:14px;text-align:center}.service-card{display:grid;gap:12px}.readable{max-width:860px}.policy-article p{margin:0 0 14px}.empty-state{display:grid;justify-items:center;gap:12px;padding:42px 24px;text-align:center}.empty-state h2{margin:0;font-size:26px}.skeleton-title{width:220px;height:28px;border-radius:999px;background:#e9edf2}.skeleton-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}.skeleton-card{min-height:180px;border-radius:var(--radius-card);background:linear-gradient(90deg,#eef2f7 25%,#f8fafc,#eef2f7 75%);background-size:240% 100%;animation:shimmer 1.6s linear infinite}@keyframes shimmer{0%{background-position:120% 0}to{background-position:-120% 0}}.mobile-sticky-action{position:fixed;right:0;bottom:56px;left:0;z-index:45;display:none;grid-template-columns:1fr 1fr;gap:10px;padding:10px 14px;border-top:1px solid var(--border);background:#fffffff5;-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px)}@media (max-width: 1279px){.learning-page{grid-template-columns:minmax(0,1fr) 280px}}@media (max-width: 1023px){main{width:min(100% - 32px,900px)}.home-hero,.detail-hero,.detail-layout,.redeem-layout,.learning-page,.profile-grid{grid-template-columns:1fr}.course-action-panel,.redeem-form,.lesson-sidebar{position:static}.course-grid,.skeleton-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.detail-main{grid-column:auto}.value-grid,.quick-strip{grid-template-columns:1fr}}@media (max-width: 767px){.site-header{min-height:56px;padding:0 16px}.desktop-nav,.account-status{display:none}.mobile-nav{display:grid}main{width:min(100% - 24px,560px);padding:18px 0 112px}.page-title{align-items:stretch;flex-direction:column}.page-title h1,.home-copy h1,.auth-card h1,.success-card h1,.payment-card h1{font-size:30px}.home-hero{gap:20px;padding:12px 0 22px}.course-grid,.skeleton-grid{grid-template-columns:1fr}.course-card-body,.card,.empty-state,.my-course-card,.identity-card,.lesson-sidebar,.service-card,.course-action-panel,.auth-card,.success-card,.payment-card,.detail-cover-panel,.hero-course-card{padding:16px}.lesson-rows div,.lesson-rows button{grid-template-columns:34px minmax(0,1fr)}.lesson-rows small{grid-column:2 / 3}.materials-list button,.identity-card,.my-course-card{grid-template-columns:1fr}.course-card-actions{grid-template-columns:1fr 1fr}.mobile-sticky-action{display:grid}.actions .btn,.course-card-actions .btn{flex:1 1 130px}}@media (max-width: 414px){main{width:min(100% - 20px,394px)}.brand{min-width:0}.btn{min-height:40px;padding:0 12px;font-size:14px}.hero-course-card h2,.course-card h2,.card h2,.my-course-card h2{font-size:20px}.course-card-actions,.mobile-sticky-action{grid-template-columns:1fr}.compact-facts div,.status-list div{align-items:flex-start;flex-direction:column;gap:3px}.compact-facts dd,.status-list dd{text-align:left}}