:root{font-family:system-ui,'Microsoft YaHei',sans-serif;color:#19334e;background:#f7faff;color-scheme:light}*{box-sizing:border-box}body{margin:0}a{color:inherit;text-decoration:none}button{font:inherit;cursor:pointer}button:focus-visible,a:focus-visible{outline:2px solid #2782ee;outline-offset:3px}.course-header{max-width:1200px;margin:20px auto;display:flex;align-items:center;gap:28px;padding:16px 24px;background:#fff;border:1px solid #dce9f9;border-radius:20px}.course-brand{font-size:22px;font-weight:750;display:flex;align-items:center;gap:9px}.course-brand img{width:38px;height:38px;object-fit:contain}.course-header nav{display:flex;gap:24px;flex:1;font-size:14px}.course-header nav a[aria-current]{color:#1680f4}#courseAccount{font-size:14px}main{max-width:1200px;margin:auto;padding:24px 24px 64px}.eyebrow{font-size:12px;color:#4484bb}h1{font-size:34px;line-height:1.25;margin:12px 0}p{line-height:1.7;color:#6b8096}.course-intro{display:flex;align-items:center;justify-content:space-between;gap:20px;margin-bottom:28px}.course-intro p{font-size:14px}.course-facts{display:flex;flex-wrap:wrap;gap:14px;font-size:12px;color:#64809b}.primary,.secondary{display:inline-block;padding:12px 16px;border-radius:10px;font-size:14px;border:0}.primary{color:#fff;background:#1679ed}.secondary{color:#357bb6;background:#edf5ff;border:1px solid #d8e9fa}.course-layout{display:grid;grid-template-columns:minmax(0,1fr) 300px;gap:22px}.course-main{min-width:0}.course-media{aspect-ratio:16/9;border-radius:18px;overflow:hidden;position:relative;display:flex;align-items:center;justify-content:center;background:#102940;color:#fff;padding:24px;text-align:center}.course-media img{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;opacity:.36}.course-media .media-info{position:relative;max-width:450px;padding:20px;border-radius:14px;background:#102940c9}.course-media h2{font-size:24px;margin:8px}.course-media p{color:#d2e2f1;font-size:13px;margin:10px 0}.course-media .media-tag{font-size:11px;letter-spacing:.03em;color:#bfdcff}.course-article,.course-sidebar{background:#fff;border:1px solid #e0eaf5;border-radius:18px;padding:24px}.course-article{margin-top:18px}.course-article h2{font-size:23px;margin:6px 0 10px}.course-article h3{font-size:15px;margin:24px 0 8px}.course-article p,.course-article li{font-size:14px;line-height:1.85}.course-article ol{padding-left:22px}.course-article li{margin:8px 0}.lesson-tip{background:#f2f7fd;border-radius:10px;padding:12px 14px}.course-article .primary{margin-top:10px}.course-sidebar{padding:20px;align-self:start}.course-sidebar h2{font-size:17px;margin:0}.course-sidebar>p{font-size:12px;margin:8px 0 16px}.course-sidebar ol{list-style:none;margin:0;padding:0}.chapter-button{width:100%;text-align:left;border:0;background:transparent;border-radius:10px;padding:12px 10px;display:flex;gap:10px;color:#334d67;align-items:center}.chapter-button:hover{background:#f5f8fc}.chapter-button[aria-current=true]{background:#eaf3ff;color:#1472dd}.chapter-number{font-size:12px;color:#90a5b9}.chapter-copy{flex:1}.chapter-copy b{font-weight:550;font-size:13px;display:block}.chapter-copy small{display:block;font-size:11px;color:#7b91a7;margin-top:5px}.course-sidebar-note{font-size:11px;color:#7990a6;line-height:1.7;margin-top:16px;padding-top:16px;border-top:1px solid #e5edf7}.course-navigation{display:flex;gap:10px;justify-content:space-between;margin-top:16px}.course-navigation button{border:1px solid #dce7f5;background:#fff;border-radius:9px;padding:10px 14px;color:#3676b1}.course-navigation button:disabled{opacity:.4;cursor:default}.course-next{margin-top:38px}.course-next h2{font-size:20px}.course-next>div{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}.course-next a{background:#fff;border:1px solid #e0eaf5;border-radius:14px;padding:20px}.course-next b{font-size:15px;display:block}.course-next span{font-size:12px;color:#7a8fa3;display:block;margin-top:10px}dialog{width:min(440px,calc(100vw - 32px));padding:28px;border:1px solid #d8e7f7;border-radius:18px;color:#19334e}dialog::backdrop{background:#17344f77}dialog h2{font-size:22px}dialog p{font-size:14px}dialog a{margin:8px 8px 0 0}#courseGateClose{float:right;background:transparent;border:0;font-size:22px;color:#7b8ca1}@media(max-width:820px){.course-header{margin:10px 12px;padding:14px;gap:14px}.course-header nav{gap:12px}.course-brand{font-size:18px}.course-brand img{width:28px;height:28px}main{padding:20px 16px}.course-intro{align-items:start;flex-direction:column}h1{font-size:28px}.course-layout{grid-template-columns:1fr}.course-sidebar{grid-row:1}.course-sidebar ol{display:grid;grid-template-columns:1fr 1fr;gap:3px}.course-sidebar-note{display:none}.course-next>div{grid-template-columns:1fr}.course-media h2{font-size:20px}}@media(max-width:460px){.course-header{flex-wrap:wrap}.course-header nav{order:3;flex-basis:100%;justify-content:center}.course-header #courseAccount{margin-left:auto}.course-sidebar{padding:14px}.chapter-button{padding:10px 6px}.chapter-copy b{font-size:12px}.course-media{padding:10px}.course-media .media-info{padding:14px}.course-article{padding:20px}}
:root [hidden]{display:none!important}.gallery-heading h1{font-size:30px;margin:6px 0}.gallery-heading p{font-size:14px;margin-bottom:24px}.gallery-tools{display:flex;justify-content:space-between;gap:16px;margin:24px 0}.gallery-tools nav{display:flex;flex-wrap:wrap;gap:8px}.gallery-tools button,.note-tabs button{background:transparent;border:0;padding:9px 14px;border-radius:8px;color:#71879c}.gallery-tools button[aria-pressed=true],.note-tabs button[aria-pressed=true]{background:#e8f2ff;color:#1473df}.gallery-tools input{font:inherit;font-size:13px;width:240px;padding:10px 14px;border:1px solid #dce8f7;border-radius:10px;background:#fff}.course-cards{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:20px}.course-preview{background:#fff;border:1px solid #deebf7;border-radius:16px;overflow:hidden;transition:transform .18s,box-shadow .18s}.course-preview:hover{transform:translateY(-3px);box-shadow:0 10px 26px #215ba110}.preview-cover{aspect-ratio:16/9;position:relative;overflow:hidden}.preview-cover img{width:100%;height:100%;object-fit:cover}.preview-cover span{position:absolute;left:12px;bottom:12px;background:#15354edb;padding:5px 9px;color:#fff;font-size:11px;border-radius:6px}.preview-copy{padding:18px}.preview-copy h2{font-size:17px;margin:0 0 9px}.preview-copy p{font-size:12px;margin:0 0 12px}.preview-copy small,.gallery-footnote{font-size:12px;color:#889db1}.gallery-footnote{margin-top:24px}.lesson-heading{display:flex;gap:18px;align-items:center;margin:0 0 18px;font-size:13px}.lesson-heading a{color:#337cb8}.lesson-heading span{color:#7f93a7}.course-layout{align-items:start}.course-sidebar{height:var(--player-height,420px);display:flex;flex-direction:column;overflow:hidden;padding:18px 12px}.course-sidebar h2{margin:0 8px 14px;flex-shrink:0}.course-sidebar ol{overflow:auto;min-height:0;flex:1;scrollbar-width:thin;scrollbar-color:#c8d8e9 transparent;overscroll-behavior:contain}.course-media{padding:0;background:#111c27;border-radius:14px}.course-media video{position:absolute;inset:0;width:100%;height:100%;object-fit:contain;background:#111c27}.player-top{position:absolute;top:12px;right:12px;left:12px;display:flex;justify-content:space-between;gap:8px;align-items:center;z-index:2;pointer-events:none}.player-top span{color:#fff;background:#132638b8;border-radius:6px;padding:6px 9px;font-size:11px}.player-nav{display:flex;gap:5px;pointer-events:auto}.player-nav button{border:1px solid #ffffff38;background:#132638b8;color:#fff;border-radius:6px;padding:6px 10px;font-size:12px}.player-nav button:disabled{opacity:.4;cursor:default}.course-media .media-info{padding:20px}.course-notes{background:#fff;border:1px solid #e0eaf5;border-radius:16px;margin-top:20px;padding:24px 28px}.course-notes h1{font-size:24px;margin:0 0 8px}.course-notes p{font-size:14px;margin:8px 0}.description-meta{font-size:12px;color:#8a9cb0}.note-tabs{display:flex;gap:10px;border-bottom:1px solid #e7edf5;padding:14px 0 12px;margin-bottom:16px}.course-notes #courseArticle ol{padding-left:22px;max-width:850px}.course-notes #courseArticle li{font-size:14px;line-height:1.9;margin:7px 0}.course-notes .lesson-tip{max-width:900px;font-size:13px}.resource-download{border:1px solid #dce9fa;background:#f5f9ff;border-radius:9px;padding:10px 15px;color:#2676b7;font-size:13px}.course-community{display:flex;align-items:center;justify-content:space-between;padding:20px 24px;background:#edf5ff;border-radius:14px;margin-top:18px}.course-community b{font-size:14px}.course-community p{font-size:12px;margin:5px 0 0}.course-community button{border:1px solid #d4e3f5;border-radius:8px;padding:9px 14px;background:#fff;color:#8196ac;cursor:default}@media(max-width:820px){.course-cards{grid-template-columns:repeat(2,minmax(0,1fr))}.gallery-tools{flex-direction:column}.gallery-tools input{width:100%}.course-sidebar{grid-row:auto;height:230px}.course-sidebar ol{display:block}.course-notes{padding:20px}.course-notes h1{font-size:21px}}@media(max-width:460px){.course-cards{grid-template-columns:1fr}.course-community{padding:18px;gap:12px}.player-top{top:8px;right:8px;left:8px}.player-top span{font-size:10px}.player-nav button{font-size:10px;padding:5px 7px}}
.course-community img{width:108px;height:108px;flex-shrink:0}.media-error{position:absolute;inset:auto 20px 70px;background:#203e59e8;padding:10px;border-radius:8px;color:#fff;font-size:13px}
.course-media[data-playing=true] .player-top{display:none}
.player-top>span{color:#2469b0;background:#f0f7fff5;border:1px solid #d5e6fb}
.player-nav{gap:8px}.player-nav button{color:#1768c4;background:#f8fbfff5;border:1px solid #c7ddf9;padding:7px 12px;box-shadow:0 2px 8px #173c6410}.player-nav button:hover:not(:disabled){background:#e7f2ff;border-color:#99c3f7}.player-nav button:disabled{opacity:1;color:#8a9db3;background:#eef3f8de;border-color:#dce5ef}
.course-resource-list{display:flex;flex-wrap:wrap;align-items:stretch;gap:14px;margin:18px 0 8px}.course-resource-list .resource-download{display:inline-flex;align-items:center;justify-content:flex-start;min-height:46px;max-width:100%;margin:0;padding:12px 18px;line-height:1.5;white-space:normal;overflow-wrap:anywhere;color:#1768c4;background:#f6faff;border-color:#cddff7}.course-resource-list .resource-download:hover{background:#eaf4ff;border-color:#a7caf7}
@media(max-width:460px){.course-resource-list{flex-direction:column;gap:12px;margin-top:16px}.course-resource-list .resource-download{width:100%;padding:13px 16px}.player-nav{gap:6px}.player-nav button{padding:6px 9px}}
/* Honest production empty state; uses the existing white / pale-blue academy palette. */
.course-empty{grid-column:1/-1;text-align:center;padding:52px 28px;background:#fff;border:1px solid #d9e7fb;border-radius:22px;min-width:0}.course-empty h2{margin:0 0 14px;font-size:24px}.course-empty p{max-width:580px;margin:0 auto 22px;line-height:1.9;color:#7088a7}.course-empty button,.course-empty a{display:inline-flex;align-items:center;justify-content:center;box-sizing:border-box;min-height:42px;padding:10px 18px;margin:6px;border:1px solid #cbdffb;border-radius:11px;background:#edf5ff;color:#1675ea;font:inherit;text-decoration:none;cursor:pointer}.course-empty a{background:#267bf0;color:#fff;border-color:#267bf0}@media(max-width:600px){.course-empty{padding:36px 16px}.course-empty h2{font-size:21px}.course-empty button,.course-empty a{padding:9px 14px}}