*{box-sizing:border-box}html,body,#root{min-width:320px;min-height:100vh}body{color:#f7fafc;background:#0a0f17;margin:0;font-family:Inter,Microsoft YaHei,system-ui,sans-serif}button,a.download-button,a.secondary-button{color:#16202a;cursor:pointer;background:#f7fafc;border:1px solid #d7e0ea;border-radius:6px;justify-content:center;align-items:center;min-width:112px;min-height:44px;padding:0 18px;font-size:16px;font-weight:700;text-decoration:none;display:inline-flex}button:focus-visible,a:focus-visible{outline-offset:3px;outline:3px solid #70b7ff}button:disabled{color:#7b8794;cursor:not-allowed;opacity:1;background:#263241;border-color:#334155}.classroom-player{background:#0a0f17;grid-template-rows:auto minmax(0,1fr);width:100vw;min-height:100vh;display:grid}.classroom-header{background:#111a26;border-bottom:1px solid #263244;grid-template-columns:auto minmax(0,1fr) auto;align-items:center;gap:18px;padding:14px 20px;display:grid}.header-copy{min-width:0}h1,h2{letter-spacing:0;margin:0}h1{color:#fff;text-overflow:ellipsis;white-space:nowrap;font-size:28px;font-weight:850;line-height:1.2;overflow:hidden}h2{color:#fff;font-size:clamp(34px,5vw,68px);font-weight:850;line-height:1.12}.return-button,a.secondary-button{color:#dbeafe;background:#172539;border-color:#31506d;min-width:88px}.courseware-badge{color:#dbeafe;white-space:nowrap;background:#172539;border:1px solid #31506d;border-radius:999px;padding:8px 12px;font-size:15px;font-weight:700}.return-message,.player-message{color:#facc15;margin:8px 0 0;font-size:15px;line-height:1.45}.pdf-stage{grid-template-rows:auto minmax(0,1fr) auto;gap:10px;min-height:0;padding:12px;display:grid}.pdf-stage:fullscreen{background:#050914;width:100vw;height:100vh;padding:8px}.pdf-toolbar{background:#111a26f5;border:1px solid #263244;border-radius:8px;flex-wrap:wrap;justify-content:center;align-items:center;gap:10px;padding:10px;display:flex}.page-field{color:#e5edf6;align-items:center;gap:8px;font-weight:700;display:inline-flex}.page-field input{color:#fff;width:76px;height:44px;font:inherit;text-align:center;background:#0f1824;border:1px solid #456174;border-radius:6px;font-weight:800}.total-pages{color:#cbd5e1;font-size:16px;font-weight:700}.pdf-canvas{background:#111827;border:1px solid #263244;border-radius:8px;min-height:0;overflow:hidden}.pdf-preview{background:#fff;border:0;width:100%;height:calc(100vh - 118px);min-height:620px;display:block}.pdf-stage:fullscreen .pdf-preview{height:calc(100vh - 76px);min-height:0}.pdf-loading{color:#dbeafe;place-items:center;height:calc(100vh - 118px);min-height:620px;font-size:24px;font-weight:800;display:grid}.powerpoint-player{background:#080d14}.powerpoint-stage{place-items:center;min-height:0;padding:clamp(20px,4vh,40px);display:grid}.powerpoint-card{text-align:center;justify-items:center;gap:16px;width:min(760px,100%);padding:clamp(24px,4vw,48px);display:grid}.powerpoint-card h2{overflow-wrap:anywhere;max-width:100%;font-size:clamp(32px,4vw,56px)}.courseware-kind{color:#93c5fd;margin:0;font-size:20px;font-weight:850}.ppt-filename,.ppt-intro,.teacher-help{color:#cbd5e1;max-width:760px;margin:0;font-size:17px;line-height:1.55}.ppt-filename{color:#9fb0c3;font-size:16px}.ppt-intro{color:#e6edf5;margin-top:6px;font-size:19px}.primary-play-button{color:#fff;background:#2f6fec;border-color:#76a9f2;width:min(360px,100%);min-height:56px;padding:0 28px;font-size:20px;box-shadow:0 12px 28px #00000047}.player-page{grid-template-rows:auto minmax(0,1fr);gap:20px;width:min(1280px,100vw);height:100dvh;margin:0 auto;padding:24px;display:grid;overflow:hidden}.viewer-shell{align-content:start;gap:16px;display:grid}.viewer-shell:fullscreen{background:#050914;width:100vw;height:100vh;padding:20px}.player-stage{aspect-ratio:16/9;touch-action:pan-y;background:#101827;border:1px solid #334155;border-radius:8px;place-items:center;width:100%;min-height:min(70vh,720px);display:grid;position:relative;overflow:hidden;box-shadow:0 20px 60px #0000005c}.viewer-shell:fullscreen .player-stage{aspect-ratio:auto;height:calc(100vh - 126px);min-height:0}.courseware-image{object-fit:contain;object-position:center;-webkit-user-select:none;user-select:none;width:100%;height:100%;display:block}.courseware-image.is-loading{opacity:0}.slide-overlay,.slide-message{text-align:center;background:#070c14c7;place-items:center;padding:32px;display:grid;position:absolute;inset:0}.slide-message{align-content:center;gap:14px}.slide-message p,.status-card p{color:#d7e3ee;max-width:720px;margin:0 auto;font-size:18px;line-height:1.65}.viewer-controls,.status-actions{flex-wrap:wrap;justify-content:center;align-items:center;gap:12px;display:flex}.status-actions{margin-top:22px}.page-indicator{text-align:center;color:#f7fafc;min-width:188px;font-size:20px;font-weight:850}.fullscreen-button{color:#0f2c4d;background:#dbeafe;min-width:124px}.status-page{color:#f7fafc;text-align:center;background:#0b1018;place-items:center;min-height:100vh;padding:32px;display:grid}.status-card{width:min(760px,100%)}.eyebrow{color:#8fbce6;margin:0 0 8px;font-size:15px;font-weight:700}@media (width>=1600px){.pdf-preview,.pdf-loading{height:calc(100vh - 108px)}}@media (width<=920px){.classroom-header{grid-template-columns:1fr;align-items:stretch}h1{white-space:normal;font-size:24px}.courseware-badge,.return-button{width:fit-content}.pdf-preview,.pdf-loading{height:calc(100vh - 220px);min-height:420px}}@media (width<=720px){button,a.download-button,a.secondary-button{width:100%;min-height:52px}.pdf-toolbar{flex-direction:column;align-items:stretch}.page-field{justify-content:center}.powerpoint-stage{padding:18px}}.gameplay-screen-page{box-sizing:border-box;color:#f5f7f8;background:#0b0f12;min-height:100vh;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Microsoft YaHei,sans-serif;overflow-x:hidden}.gameplay-screen-page:fullscreen{height:100vh;overflow-y:auto}.gameplay-screen-page.status-only{place-items:center;min-height:100vh;padding:32px;display:grid}.gameplay-screen-status{box-sizing:border-box;background:#151b1f;border:1px solid #344047;border-radius:8px;width:min(760px,100%);padding:40px;box-shadow:0 24px 72px #00000052}.gameplay-screen-status h1{letter-spacing:0;margin:0;font-size:48px;line-height:1.15}.gameplay-screen-status p{color:#bdc8cc;margin:18px 0 0;font-size:21px;line-height:1.7}.gameplay-screen-status button,.screen-resource-panel button,.screen-fullscreen-button{box-sizing:border-box;color:#fff;letter-spacing:0;cursor:pointer;background:#1268c4;border:1px solid #2878d0;border-radius:6px;min-height:46px;padding:10px 20px;font-size:17px;font-weight:800}.gameplay-screen-status button{margin-top:24px}.gameplay-screen-topbar{z-index:20;box-sizing:border-box;-webkit-backdrop-filter:blur(14px);backdrop-filter:blur(14px);background:#0f1417f0;border-bottom:1px solid #2a343a;justify-content:space-between;align-items:center;gap:24px;min-height:84px;padding:14px max(28px,50vw - 800px);display:flex;position:sticky;top:0}.gameplay-screen-topbar>div{flex-direction:column;align-items:flex-start;gap:2px;min-width:0;display:flex}.gameplay-screen-topbar strong{color:#f5f7f8;text-overflow:ellipsis;white-space:nowrap;font-size:24px;line-height:1.2;overflow:hidden}.screen-topbar-label{color:#79b8ff;flex:none;font-size:14px;font-weight:800}.screen-fullscreen-button{background:#20292e;flex:none;min-width:112px;min-height:50px}.screen-fullscreen-button:hover,.screen-fullscreen-button:focus-visible{background:#1268c4}.gameplay-screen-content{width:min(1600px,100% - 56px);margin:0 auto;padding:28px 0 72px}.gameplay-screen-hero{background:#151b1f;border:1px solid #344047;border-radius:8px;min-height:300px;display:grid;overflow:hidden;box-shadow:0 24px 60px #00000038}.gameplay-screen-hero.has-image{grid-template-columns:minmax(0,44fr) minmax(0,56fr);height:400px;min-height:0}.screen-hero-media{background:#080b0d;border-right:1px solid #344047;place-items:center;min-width:0;min-height:0;display:grid;overflow:hidden}.screen-hero-media img{object-fit:contain;width:100%;height:100%;max-height:100%;display:block}.screen-hero-copy{box-sizing:border-box;flex-direction:column;justify-content:center;min-width:0;padding:40px 48px;display:flex}.screen-eyebrow{color:#79b8ff;margin:0 0 12px;font-size:17px;font-weight:800}.screen-hero-copy h1{color:#fff;letter-spacing:0;margin:0;font-size:52px;line-height:1.12}.screen-meta-row{flex-wrap:wrap;gap:12px;margin-top:22px;display:flex}.screen-meta-row span,.screen-resource-meta span{box-sizing:border-box;color:#dce3e6;background:#20292e;border:1px solid #3f4d55;border-radius:6px;align-items:center;min-height:34px;padding:5px 12px;font-size:16px;font-weight:700;display:inline-flex}.screen-meta-row span:nth-child(2){color:#f2bd70;background:#2b241a;border-color:#684b26}.screen-content-grid{grid-template-columns:repeat(auto-fit,minmax(min(100%,430px),1fr));gap:20px;margin-top:24px;display:grid}.screen-section{box-sizing:border-box;background:#151b1f;border:1px solid #344047;border-radius:8px;min-width:0;padding:30px}.screen-section h2{color:#fff;letter-spacing:0;margin:0;font-size:30px;line-height:1.3}.screen-copy-section p{color:#d5dde0;white-space:pre-wrap;margin:18px 0 0;font-size:22px;line-height:1.8}.screen-text-list{color:#d5dde0;margin:18px 0 0;padding-left:30px;font-size:22px;line-height:1.75}.screen-text-list li+li{margin-top:10px}.resource-section{margin-top:24px}.screen-section-heading{margin-bottom:22px;display:block}.screen-section-heading .screen-eyebrow{margin:0 0 6px}.screen-resource-grid{grid-template-columns:repeat(2,minmax(0,1fr));align-items:start;gap:20px;display:grid}.screen-resource-grid>:only-child{grid-column:1/-1}.screen-resource-panel{box-sizing:border-box;background:#101518;border:1px solid #3b474e;border-radius:8px;flex-direction:column;align-self:start;min-width:0;padding:22px;display:flex;overflow:hidden}.screen-resource-heading{justify-content:space-between;align-items:flex-start;gap:18px;min-width:0;margin-bottom:18px;display:flex}.screen-resource-heading>div:first-child{align-items:center;gap:12px;min-width:0;display:flex}.screen-resource-kind{box-sizing:border-box;color:#fff;background:#b93d3d;border-radius:6px;place-items:center;min-width:58px;min-height:34px;padding:5px 8px;font-size:13px;font-weight:900;display:inline-grid}.screen-resource-panel--video .screen-resource-kind{background:#6c4bc3}.screen-resource-panel h3{color:#fff;letter-spacing:0;margin:0;font-size:26px;line-height:1.35}.screen-resource-meta{flex-wrap:wrap;justify-content:flex-end;gap:8px;min-width:0;display:flex}.screen-resource-meta span{text-overflow:ellipsis;white-space:nowrap;max-width:260px;font-size:14px;overflow:hidden}.screen-pdf-preview-state,.screen-video-state{color:#9eacb3;background:#0a0e10;border:1px solid #344047;border-radius:8px;flex:1;place-items:center;min-height:420px;font-size:18px;display:grid}.screen-pdf-preview-shell{background:#fff;border:1px solid #344047;border-radius:8px;width:100%;height:62vh;min-height:520px;max-height:780px;overflow:hidden}.screen-pdf-preview{background:#fff;border:0;width:100%;height:100%;display:block}.screen-video{aspect-ratio:16/9;object-fit:contain;background:#000;border-radius:8px;width:100%;max-height:62vh;display:block}.screen-resource-error{box-sizing:border-box;background:#241817;border:1px solid #69413d;border-radius:8px;place-content:center;justify-items:center;gap:18px;min-height:220px;padding:24px;display:grid}.screen-resource-error p{color:#ffb4a8;text-align:center;margin:0;font-size:18px;line-height:1.6}@media (width<=1180px){.gameplay-screen-hero.has-image,.screen-resource-grid{grid-template-columns:1fr}.gameplay-screen-hero.has-image{height:auto}.screen-hero-media{aspect-ratio:16/9;border-bottom:1px solid #344047;border-right:0;width:100%;min-height:0}.screen-resource-grid>:only-child{grid-column:auto}.screen-pdf-preview-shell{height:68vh}}@media (width<=760px){.gameplay-screen-page.status-only{padding:16px}.gameplay-screen-status{padding:28px}.gameplay-screen-status h1{font-size:36px}.gameplay-screen-topbar{padding:10px 16px}.gameplay-screen-topbar strong{display:none}.gameplay-screen-content{width:min(100% - 28px,1600px);padding:20px 0 44px}.screen-hero-copy,.screen-section{padding:22px}.screen-hero-copy h1{font-size:40px}.screen-resource-heading{flex-direction:column}.screen-resource-meta{justify-content:flex-start}.screen-pdf-preview-state,.screen-video-state,.screen-pdf-preview-shell{min-height:360px}}.courseware-page-viewer{color:#f3f6f7;background:#000;flex-direction:column;flex:1;min-height:0;display:flex;overflow:hidden}.courseware-stage{background:#000;flex:1;place-items:center;min-width:0;min-height:0;display:grid;position:relative}.courseware-media-frame{background:#000;flex:none;place-items:center;width:100%;max-width:100%;height:100%;max-height:100%;display:grid}.courseware-image,.courseware-video{object-fit:contain;object-position:center;background:#000;width:100%;max-width:100%;height:100%;max-height:100%;display:block}.courseware-media-status{text-align:center;color:#fff;background:#050708d1;place-content:center;gap:12px;display:grid;position:absolute;inset:0}.courseware-controls{background:#12191c;flex-wrap:wrap;flex:none;justify-content:center;align-items:center;gap:8px;padding:10px 14px;display:flex}.courseware-controls .page-indicator{text-align:center;min-width:150px}.courseware-page-viewer .operation-hint,.courseware-page-viewer .fullscreen-message{text-align:center;color:#bdc8cc;background:#12191c;margin:0;padding:5px 14px}.courseware-page-viewer:fullscreen{width:100vw;height:100vh}.courseware-page-viewer:fullscreen .courseware-stage{width:100%}@media (width<=720px){.courseware-controls{padding:8px}.courseware-controls button{min-height:40px}.courseware-page-viewer .operation-hint{display:none}}.classroom-player{height:100dvh;min-height:0;overflow:hidden}.classroom-header{background:#101923;border-bottom-color:#223044;gap:14px;min-height:58px;padding:8px clamp(12px,1.5vw,22px)}.classroom-header h1{font-size:clamp(19px,1.5vw,24px);font-weight:800}.classroom-header .return-button{background:#152338;border-color:#36516c;min-width:104px}.classroom-header .courseware-badge{color:#c8d9ea;background:#15202d;border-color:#304960;padding:6px 10px;font-size:13px}.control-group{justify-content:center;align-items:center;gap:8px;min-width:0;display:inline-flex}.pdf-stage{gap:8px;padding:8px}.pdf-stage:fullscreen{padding:6px}.pdf-toolbar{background:#0f1721fa;border-color:#223044;border-radius:6px;grid-template-columns:minmax(0,1fr) auto minmax(0,1fr);justify-content:space-between;gap:8px 14px;min-height:54px;padding:6px 10px;display:grid}.pdf-toolbar .pagination-controls{justify-self:start}.pdf-toolbar .classroom-actions{grid-column:2;justify-self:center}.pdf-toolbar button,.pdf-toolbar a.download-button,.courseware-controls button{min-width:92px;min-height:40px;padding:0 14px;font-size:15px}.next-page-button,.video-action-button{color:#fff;background:#2f6fed;border-color:#397be8}.quiet-button{color:#142333;background:#eef3f7;border-color:#53687c}.utility-button,.pdf-toolbar a.utility-button{color:#c8d3dc;background:#17222d;border-color:#33475a;min-width:86px;font-weight:650}.page-field input{width:60px;height:40px}.total-pages{font-size:15px}.pdf-canvas{background:#05080d;border-color:#223044;border-radius:6px}.pdf-preview,.pdf-loading{height:100%;min-height:0}.pdf-stage:fullscreen .pdf-preview{height:100%}.player-page{gap:10px;width:100vw;padding:10px clamp(10px,1.5vw,24px)}.status-page{padding:clamp(24px,5vw,56px)}.status-card{background:#101923;border:1px solid #26384a;border-radius:8px;padding:clamp(28px,5vw,48px);box-shadow:0 20px 60px #0000003d}.status-card h1{font-size:clamp(28px,4vw,42px)}.status-card p{margin-top:14px}.courseware-controls{background:#10171c;border-top:1px solid #22303a;gap:8px 14px;min-height:58px;padding:8px clamp(10px,1.4vw,20px)}.courseware-controls .page-indicator{color:#fff;white-space:nowrap;min-width:156px;padding:0 8px;font-size:18px;font-weight:800}.courseware-controls .fullscreen-button{color:#15375e;background:#d9e8fb;border-color:#77a8ed}.courseware-page-viewer .operation-hint,.courseware-page-viewer .fullscreen-message{color:#9eabb4;background:#10171c;padding:0 14px 8px;font-size:13px;line-height:1.4}.courseware-page-viewer:fullscreen{grid-template-rows:minmax(0,1fr) auto auto;width:100vw;height:100dvh;max-height:100dvh;display:grid;overflow:hidden}.courseware-page-viewer:fullscreen .courseware-stage{grid-row:1;min-height:0}.courseware-page-viewer:fullscreen .courseware-controls{grid-row:2;min-height:48px;padding-block:5px 7px}.courseware-page-viewer:fullscreen .fullscreen-message{grid-row:3}.courseware-page-viewer:fullscreen .operation-hint{display:none}@media (width<=1100px){.pdf-toolbar{grid-template-columns:1fr;justify-content:center}.pdf-toolbar .pagination-controls{grid-column:1;justify-self:center}.pdf-toolbar .classroom-actions{grid-column:1}.courseware-controls{gap:7px 10px}.courseware-controls button{min-width:84px;padding-inline:10px}}@media (width<=720px){.classroom-header{grid-template-columns:auto minmax(0,1fr)}.classroom-header .courseware-badge{display:none}.player-page{gap:0;padding:0}.pdf-toolbar .control-group,.courseware-controls .control-group{flex-wrap:wrap}}