.platform-header{height:76px;padding:0 max(32px,calc((100vw - 1440px)/2));display:flex;align-items:center;justify-content:space-between;gap:20px;border-bottom:1px solid #dce6e8;background:var(--bg)}.platform-header-link{display:inline-flex;align-items:center;gap:12px;font-size:16px;min-height:44px}.platform-header-link:hover{color:var(--accent)}.platform-overview{width:min(1360px,calc(100% - 96px));margin:0 auto;padding:36px 0 96px}.platform-back{display:inline-flex;gap:10px;align-items:center;min-height:44px;font-size:16px;color:var(--muted)}.platform-back:hover{color:var(--accent)}.platform-eyebrow{font-size:13px;letter-spacing:.11em;text-transform:uppercase;color:var(--muted);display:flex;align-items:center;gap:22px;line-height:1.5}.platform-overview h1:focus{outline:none}.course-overview-hero{display:grid;grid-template-columns:1fr 240px;gap:80px;padding:50px 0 72px;border-bottom:1px solid var(--line)}.course-overview-hero h1{font-size:clamp(48px,6.5vw,88px);max-width:920px}.course-overview-summary{max-width:720px;font-size:22px;line-height:1.6;color:var(--muted);margin:24px 0}.course-overview-meta{display:flex;flex-wrap:wrap;gap:12px 26px;margin:26px 0 34px;font-size:16px;color:var(--muted)}.course-overview-meta span+span{padding-left:26px;border-left:1px solid var(--line)}.course-status{display:inline-flex;gap:7px;align-items:center;letter-spacing:0;text-transform:none;font-size:13px;white-space:nowrap;color:var(--accent)}.course-status:before{content:"";width:6px;height:6px;border-radius:50%;background:currentColor}.course-status.is-in-progress{color:var(--blue)}.course-status.is-planned{color:var(--muted)}.course-overview-aside{align-self:end;padding:28px 0 12px 32px;border-left:1px solid var(--line)}.course-overview-aside p{font-size:25px;letter-spacing:-.04em;line-height:1.3}.course-overview-aside>span:last-child{font-size:16px;line-height:1.9;color:var(--muted)}.course-syllabus{display:grid;grid-template-columns:.7fr 1.3fr;gap:80px;padding-top:62px}.course-syllabus-intro h2{font-size:35px;line-height:1.25;font-weight:450;letter-spacing:-.04em}.course-syllabus-intro>p:last-child{font-size:18px;line-height:1.6;color:var(--muted);max-width:290px}.course-syllabus-lessons section{margin-bottom:36px}.course-syllabus-lessons h2{font-size:21px;font-weight:500;margin:0;padding:0 0 20px;border-bottom:1px solid var(--line)}.course-syllabus-lessons ol{list-style:none;padding:0;margin:0}.course-syllabus-lessons li a{display:grid;grid-template-columns:34px 1fr 24px;gap:20px;align-items:start;padding:24px 4px;border-bottom:1px solid var(--line)}.course-syllabus-lessons li a:hover{background:var(--green-soft);padding-left:12px;padding-right:12px}.syllabus-number{font-family:IBM Plex Mono,monospace;color:var(--accent);padding-top:3px;font-size:15px}.course-syllabus-lessons h3{font-size:22px;font-weight:450;letter-spacing:-.025em;margin:0 0 9px}.course-syllabus-lessons p{font-size:16px;line-height:1.6;color:var(--muted);margin:0}.course-syllabus-lessons svg{margin-top:4px;color:var(--accent)}.platform-footer{display:flex;justify-content:space-between;align-items:center;gap:20px;padding:28px 48px;border-top:1px solid var(--line);font-size:14px;color:var(--muted)}.platform-footer a{display:inline-flex;align-items:center;gap:12px;min-height:44px}.platform-missing{min-height:calc(100svh - 76px);padding-top:100px}.platform-missing>p:not(.platform-eyebrow){font-size:20px;margin:28px 0 40px}.course-return-link{min-height:44px;display:inline-flex;align-items:center;gap:8px;padding:8px 10px;font-size:14px;color:var(--muted);border-radius:8px}.course-return-link:hover{background:var(--surface-soft);color:var(--ink)}.menu-lesson>p{font-size:13px;color:var(--muted);padding:4px 12px;margin:8px 0}.course-menu nav .menu-lesson>a{display:flex;align-items:center;gap:18px;font-size:16px;min-height:48px;padding:12px;border:1px solid transparent;border-radius:9px}.course-menu nav .menu-lesson>a:hover{background:var(--surface-soft)}.course-menu nav .menu-lesson>a[aria-current=page]{background:var(--green-soft);border-color:#badacc}.menu-all-courses{display:flex;align-items:center;gap:10px;font-size:15px;padding:12px;min-height:48px;margin:5px 4px 0;border-top:1px solid var(--line)}@media(max-width:900px){.platform-header{padding:0 24px;height:64px}.platform-overview{width:calc(100% - 48px)}.course-overview-hero{grid-template-columns:1fr;gap:20px;padding:28px 0 40px}.course-overview-aside{display:none}.course-syllabus{grid-template-columns:1fr;gap:24px;padding-top:36px}.course-syllabus-intro h2 br{display:none}.course-syllabus-intro>p:last-child{max-width:none}.platform-footer{padding:20px 24px}}@media(max-width:520px){.platform-header{padding:0 20px;gap:12px}.platform-header-link{font-size:14px;gap:8px}.platform-overview{width:calc(100% - 40px);padding-top:20px}.course-overview-hero h1{font-size:48px}.course-overview-summary{font-size:19px}.course-overview-meta{font-size:14px;gap:10px 16px}.course-overview-meta span+span{padding-left:16px}.platform-eyebrow{flex-wrap:wrap;gap:12px}.course-syllabus-lessons li a{grid-template-columns:24px 1fr 20px;gap:12px}.course-syllabus-lessons h3{font-size:21px}.course-return-link span{display:none}.course-return-link{padding:8px}.platform-footer{align-items:flex-start;font-size:13px}.platform-footer>a{max-width:180px}.classroom-footer .page-next{font-size:14px}}@font-face{font-family:Inter Variable;font-style:normal;font-display:swap;font-weight:100 900;src:url(/assets/inter-cyrillic-ext-wght-normal-BOeWTOD4.woff2) format("woff2-variations");unicode-range:U+0460-052F,U+1C80-1C8A,U+20B4,U+2DE0-2DFF,U+A640-A69F,U+FE2E-FE2F}@font-face{font-family:Inter Variable;font-style:normal;font-display:swap;font-weight:100 900;src:url(/assets/inter-cyrillic-wght-normal-DqGufNeO.woff2) format("woff2-variations");unicode-range:U+0301,U+0400-045F,U+0490-0491,U+04B0-04B1,U+2116}@font-face{font-family:Inter Variable;font-style:normal;font-display:swap;font-weight:100 900;src:url(/assets/inter-greek-ext-wght-normal-DlzME5K_.woff2) format("woff2-variations");unicode-range:U+1F00-1FFF}@font-face{font-family:Inter Variable;font-style:normal;font-display:swap;font-weight:100 900;src:url(/assets/inter-greek-wght-normal-CkhJZR-_.woff2) format("woff2-variations");unicode-range:U+0370-0377,U+037A-037F,U+0384-038A,U+038C,U+038E-03A1,U+03A3-03FF}@font-face{font-family:Inter Variable;font-style:normal;font-display:swap;font-weight:100 900;src:url(/assets/inter-vietnamese-wght-normal-CBcvBZtf.woff2) format("woff2-variations");unicode-range:U+0102-0103,U+0110-0111,U+0128-0129,U+0168-0169,U+01A0-01A1,U+01AF-01B0,U+0300-0301,U+0303-0304,U+0308-0309,U+0323,U+0329,U+1EA0-1EF9,U+20AB}@font-face{font-family:Inter Variable;font-style:normal;font-display:swap;font-weight:100 900;src:url(/assets/inter-latin-ext-wght-normal-DO1Apj_S.woff2) format("woff2-variations");unicode-range:U+0100-02BA,U+02BD-02C5,U+02C7-02CC,U+02CE-02D7,U+02DD-02FF,U+0304,U+0308,U+0329,U+1D00-1DBF,U+1E00-1E9F,U+1EF2-1EFF,U+2020,U+20A0-20AB,U+20AD-20C0,U+2113,U+2C60-2C7F,U+A720-A7FF}@font-face{font-family:Inter Variable;font-style:normal;font-display:swap;font-weight:100 900;src:url(/assets/inter-latin-wght-normal-Dx4kXJAl.woff2) format("woff2-variations");unicode-range:U+0000-00FF,U+0131,U+0152-0153,U+02BB-02BC,U+02C6,U+02DA,U+02DC,U+0304,U+0308,U+0329,U+2000-206F,U+20AC,U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD}@font-face{font-family:IBM Plex Mono;font-style:normal;font-display:swap;font-weight:400;src:url(/assets/ibm-plex-mono-cyrillic-ext-400-normal-xuaO2J-f.woff2) format("woff2"),url(/assets/ibm-plex-mono-cyrillic-ext-400-normal-DMdlQ8Kv.woff) format("woff");unicode-range:U+0460-052F,U+1C80-1C8A,U+20B4,U+2DE0-2DFF,U+A640-A69F,U+FE2E-FE2F}@font-face{font-family:IBM Plex Mono;font-style:normal;font-display:swap;font-weight:400;src:url(/assets/ibm-plex-mono-cyrillic-400-normal-BSMlKf0J.woff2) format("woff2"),url(/assets/ibm-plex-mono-cyrillic-400-normal-CEL4l2ZJ.woff) format("woff");unicode-range:U+0301,U+0400-045F,U+0490-0491,U+04B0-04B1,U+2116}@font-face{font-family:IBM Plex Mono;font-style:normal;font-display:swap;font-weight:400;src:url(/assets/ibm-plex-mono-vietnamese-400-normal-BulugwFq.woff2) format("woff2"),url(/assets/ibm-plex-mono-vietnamese-400-normal-DDuiU_S-.woff) format("woff");unicode-range:U+0102-0103,U+0110-0111,U+0128-0129,U+0168-0169,U+01A0-01A1,U+01AF-01B0,U+0300-0301,U+0303-0304,U+0308-0309,U+0323,U+0329,U+1EA0-1EF9,U+20AB}@font-face{font-family:IBM Plex Mono;font-style:normal;font-display:swap;font-weight:400;src:url(/assets/ibm-plex-mono-latin-ext-400-normal-BmRBH3aV.woff2) format("woff2"),url(/assets/ibm-plex-mono-latin-ext-400-normal-D3D2R8hC.woff) format("woff");unicode-range:U+0100-02BA,U+02BD-02C5,U+02C7-02CC,U+02CE-02D7,U+02DD-02FF,U+0304,U+0308,U+0329,U+1D00-1DBF,U+1E00-1E9F,U+1EF2-1EFF,U+2020,U+20A0-20AB,U+20AD-20C0,U+2113,U+2C60-2C7F,U+A720-A7FF}@font-face{font-family:IBM Plex Mono;font-style:normal;font-display:swap;font-weight:400;src:url(/assets/ibm-plex-mono-latin-400-normal-DMJ8VG8y.woff2) format("woff2"),url(/assets/ibm-plex-mono-latin-400-normal-CvHOgSBP.woff) format("woff");unicode-range:U+0000-00FF,U+0131,U+0152-0153,U+02BB-02BC,U+02C6,U+02DA,U+02DC,U+0304,U+0308,U+0329,U+2000-206F,U+20AC,U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD}@supports (appearance: base-select) and selector(select::picker(select)){.classroom-app .interaction-stage select:not([multiple]):not([size]),.classroom-app .interaction-stage select:not([multiple]):not([size])::picker(select){appearance:base-select}.classroom-app .interaction-stage select:not([multiple]):not([size]){color-scheme:light;transition:none}.classroom-app .interaction-stage select:not([multiple]):not([size])::picker(select){color:var(--ink, #213744);background:var(--select-surface, #fff);border:1px solid var(--line, #b9ccd5);border-radius:9px;padding:4px;box-shadow:0 8px 24px #233f501f;min-inline-size:anchor-size(width);max-inline-size:calc(100vw - 24px);max-block-size:min(320px,60dvh);overflow:auto;opacity:1;animation:none;transition:none}.classroom-app .interaction-stage select:not([multiple]):not([size]) option{min-block-size:44px;padding:9px 12px;border-radius:5px;font:inherit;color:var(--ink, #213744);background:var(--select-surface, #fff);white-space:normal;opacity:1;animation:none;transition:none}.classroom-app .interaction-stage select:not([multiple]):not([size]) option:is(:hover,:focus,:checked){color:var(--ink, #213744);background:var(--select-highlight, #e7f2f5)}.classroom-app .interaction-stage select:not([multiple]):not([size]) option:focus-visible{outline:2px solid var(--blue, #277995);outline-offset:-2px}}:root{font-family:Inter Variable,Microsoft YaHei,sans-serif;color:var(--ink);background:var(--bg);font-synthesis:none;color-scheme:light;--ink:#203747;--muted:#526976;--line:#c5d6de;--accent:#146c57;--blue:#2269a3;--amber:#8b580c;--red:#b03f42;--surface:#fff;--bg:#f7f9f8;--surface-soft:#edf4f6;--green-soft:#e4f3ec;--blue-soft:#e6f0fa;--amber-soft:#fff2d9;--red-soft:#fbe9e7;--header-height:60px;--page-gutter:40px;--ease:cubic-bezier(.2,.7,.2,1)}*{box-sizing:border-box}body{margin:0}button,a{-webkit-tap-highlight-color:transparent;touch-action:manipulation}button,select{font:inherit;color:inherit;cursor:pointer}button:disabled{cursor:default;opacity:.4}button,a,select{transition:color .16s var(--ease),background-color .16s var(--ease),border-color .16s var(--ease),box-shadow .16s var(--ease),transform .16s var(--ease)}a{color:inherit;text-decoration:none}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,[tabindex]:focus-visible{outline:2px solid var(--blue);outline-offset:4px}::selection{color:var(--ink);background:#c8e7dd}code{font-family:IBM Plex Mono,monospace}.classroom-app{min-height:100svh;background:var(--bg);display:flex;flex-direction:column}.classroom-header{height:var(--header-height);flex:none;padding:0 var(--page-gutter);display:flex;align-items:center;justify-content:space-between;gap:12px;border-bottom:1px solid #dce6e8;background:#fff}.classroom-brand{display:flex;align-items:center;gap:14px;flex-shrink:0;border-radius:6px}.classroom-brand strong{letter-spacing:.2em;font-size:21px;font-weight:600}.brand-mark{width:24px;height:24px;border:1px solid #aac7c0;border-radius:50%;display:grid;place-items:center;box-shadow:none}.brand-mark:after{content:"";width:8px;height:8px;background:var(--accent);border-radius:50%}.brand-subject{font-size:16px;border-left:1px solid var(--line);padding-left:18px;color:var(--muted)}.header-actions{display:flex;align-items:center;gap:8px}.header-actions button{display:flex;align-items:center;justify-content:center;gap:9px;background:transparent;border:1px solid transparent;border-radius:9px;min-height:44px;padding:8px 11px;color:var(--muted);font-size:16px;white-space:nowrap}.header-actions button:hover:not(:disabled),.header-actions button[aria-expanded=true]{background:var(--surface-soft);border-color:var(--line);color:var(--ink)}.header-actions .fullscreen-action{min-width:44px}.menu-chevron{transition:transform .18s var(--ease)}button[aria-expanded=true] .menu-chevron{transform:rotate(180deg)}.classroom-main{width:min(1760px,calc(100% - var(--page-gutter)*2));margin:0 auto;flex:1;display:flex;flex-direction:column;min-width:0}.lesson-heading{padding:14px 0 6px}.lesson-eyebrow{display:flex;align-items:center;gap:10px;font-size:16px;letter-spacing:.025em;color:var(--muted);margin:0 0 8px;min-height:20px}.lesson-number{font-variant-numeric:tabular-nums;color:var(--accent)}.eyebrow-divider{height:12px;width:1px;flex:none;background:var(--line);margin:0 2px}h1{font-size:clamp(40px,3.5vw,62px);font-weight:500;letter-spacing:-.045em;line-height:1.12;margin:0;text-wrap:balance}.lesson-heading h1:focus{outline:none}.interaction-stage{margin-top:8px;flex:1;display:flex;flex-direction:column;min-width:0;animation:scene-enter .18s var(--ease) both}.interaction-scene{position:relative;isolation:isolate;min-height:420px;flex:1}.interaction-actions{display:flex;justify-content:center;align-items:center;gap:16px;padding:12px 0}.interaction-observation{display:flex;align-items:center;justify-content:space-between;gap:24px;padding:10px 0;border-top:1px solid var(--line);min-height:54px}.interaction-observation h2{font-size:22px;font-weight:450;margin:0;line-height:1.3}.reset-action{display:flex;align-items:center;gap:9px;border:1px solid transparent;border-radius:8px;background:transparent;color:var(--muted);font-size:16px;padding:9px;min-height:44px;white-space:nowrap}.reset-action:hover{color:var(--ink);background:var(--surface-soft);border-color:var(--line)}.reset-action:active svg{transform:rotate(-35deg)}.reset-action svg{transition:transform .18s var(--ease)}.classroom-footer{width:min(1760px,calc(100% - var(--page-gutter)*2));margin:6px auto 0;padding:2px 0;display:grid;grid-template-columns:1fr auto 1fr;align-items:center;gap:16px;border-top:1px solid #dce6e8;font-size:16px}.classroom-footer a{display:inline-flex;align-items:center;justify-content:center;gap:10px;min-height:44px;border-radius:9px;color:var(--muted)}.classroom-footer .page-back{justify-self:start;padding:8px 10px;margin-left:-10px}.classroom-footer .page-next{justify-self:end;padding:8px 15px;border:1px solid #c7ded7;background:var(--green-soft);color:var(--ink)}.classroom-footer a:hover{color:var(--ink);background:var(--surface-soft)}.classroom-footer .page-next:hover{border-color:#80ae9d;background:#d8eee4}.page-next svg,.page-back svg{transition:transform .16s var(--ease)}.page-next:hover svg{transform:translate(2px)}.page-back:hover svg{transform:translate(-2px)}.classroom-footer a[aria-disabled=true]{opacity:.25;pointer-events:none}.page-position{font-variant-numeric:tabular-nums;font-size:16px;color:var(--muted)}.classroom-footer i{font-style:normal;color:var(--line);margin:0 14px}.model-note{font-size:14px;color:var(--muted);letter-spacing:.03em}.action-primary,.action-secondary{border-radius:9px;display:inline-flex;gap:9px;align-items:center;justify-content:center;font-size:18px;line-height:1.25;padding:12px 20px;min-height:48px;font-weight:500;white-space:nowrap;background:var(--surface);color:var(--ink);border:1px solid #b6ccd6;box-shadow:0 1px 3px #20374708}.action-primary{background:var(--accent);color:#fff;border:1px solid var(--accent);box-shadow:0 2px 5px #20374712}.action-secondary{background:var(--surface);border:1px solid #b6ccd6;box-shadow:0 1px 3px #20374708;color:var(--ink)}.action-primary:hover:not(:disabled){filter:brightness(1.08);box-shadow:0 3px 8px #2037471a}.action-secondary:hover:not(:disabled){border-color:var(--blue);background-color:var(--blue-soft)}.action-primary:active:not(:disabled),.action-secondary:active:not(:disabled){transform:translateY(1px)}.segmented{display:inline-flex;align-items:stretch;gap:4px;padding:4px;border:1px solid #cedde2;border-radius:11px;background:#eaf1f3;max-width:100%;flex-wrap:wrap}.segmented button{border:0;border-radius:7px;background:transparent;padding:10px 16px;color:var(--muted);font-size:18px;min-height:44px}.segmented button:hover:not([aria-pressed=true]):not(:disabled){color:var(--ink);background:#ffffffa0}.segmented button[aria-pressed=true],.segmented button.active{background:#fff;color:var(--accent);box-shadow:0 1px 4px #20374718}.interaction-token{border:1px solid #b8ced7;border-radius:10px;background:var(--surface);box-shadow:0 3px 8px #2037470d;color:var(--ink)}.interaction-token:hover:not(:disabled){border-color:var(--blue);transform:translateY(-1px)}.sql-statement{display:block;margin:0;font-family:IBM Plex Mono,monospace;font-size:clamp(22px,1.7vw,30px);line-height:1.5;font-weight:400;white-space:pre-wrap;overflow-wrap:anywhere;color:var(--ink)}.sql-statement mark{background:var(--amber-soft);color:var(--amber);border-radius:3px}.sql-statement b{font-weight:400;color:var(--blue)}.material-panel{background:linear-gradient(125deg,#fff,#f0f6f8);background-size:auto;border:1px solid var(--line);border-radius:16px;box-shadow:0 5px 16px #20374709}.etched-glass{background:#eff7fa;border:1px solid #c2d9e2;border-radius:13px;box-shadow:0 3px 12px #20374708;-webkit-backdrop-filter:none;backdrop-filter:none}.material-object{position:relative;width:100%;height:100%;min-height:100px;pointer-events:none}.material-object canvas{display:block;max-width:100%;max-height:100%}.fine-label{font-size:16px;letter-spacing:.1em;text-transform:uppercase;color:var(--muted)}dialog{color:var(--ink)}dialog::backdrop{background:#20374745;-webkit-backdrop-filter:none;backdrop-filter:none;animation:none}.course-menu{position:fixed;inset:calc(var(--header-height) + 8px) var(--page-gutter) auto auto;margin:0;padding:10px;width:440px;max-width:calc(100vw - 32px);max-height:calc(100dvh - var(--header-height) - 24px);border:1px solid var(--line);border-radius:16px;background:#fff;box-shadow:0 14px 45px #20374726;overflow:hidden;animation:panel-enter .18s var(--ease)}.course-menu[open]{display:flex;flex-direction:column}.menu-title{display:flex;justify-content:space-between;align-items:center;flex:none;padding:0 6px 8px 14px}.menu-title strong{font-size:18px;font-weight:550}.menu-title button,.notice button{display:grid;place-items:center;background:transparent;border:1px solid transparent;border-radius:9px;min-width:44px;min-height:44px;color:var(--muted)}.menu-title button:hover,.notice button:hover{background:var(--surface-soft);color:var(--ink)}.course-menu nav{overflow-y:auto;overscroll-behavior:contain;padding:3px;scrollbar-width:thin;scrollbar-color:#a0b9c3 transparent}.course-menu nav>a{position:relative;display:flex;align-items:center;gap:18px;font-size:16px;min-height:48px;padding:12px;border:1px solid transparent;border-radius:9px}.menu-number{font-size:16px;font-variant-numeric:tabular-nums;color:var(--muted);min-width:22px}.menu-page-title{flex:1;line-height:1.35}.course-menu nav>a:hover{background:var(--surface-soft)}.course-menu nav>a[aria-current=page]{background:var(--green-soft);border-color:#badacc}.course-menu a[aria-current=page] .menu-number{color:var(--accent)}.menu-current{width:6px;height:6px;flex:none;border-radius:50%;background:var(--accent)}.course-menu a:focus-visible{outline-offset:-2px}.loading{min-height:420px;display:flex;align-items:center;justify-content:center;gap:14px;color:var(--muted)}.loading-indicator{width:18px;height:18px;border:2px solid #cae4d9;border-top-color:var(--accent);border-radius:50%;animation:loading-spin .8s linear infinite}.not-found,.scene-error{padding:60px 0;flex:1}.not-found p,.scene-error p{color:var(--muted);font-size:18px;line-height:1.7}.scene-error h2{font-size:28px}.notice{position:fixed;bottom:22px;left:50%;transform:translate(-50%);width:max-content;max-width:calc(100vw - 32px);display:flex;align-items:center;gap:16px;padding:6px 8px 6px 18px;background:#fff;border:1px solid var(--line);border-radius:12px;box-shadow:0 8px 24px #20374720;z-index:60;font-size:16px;line-height:1.5}@keyframes scene-enter{0%{opacity:0;transform:translateY(3px)}to{opacity:1;transform:translateY(0)}}@keyframes panel-enter{0%{opacity:0;transform:translateY(-4px)}to{opacity:1;transform:translateY(0)}}@keyframes veil-enter{0%{opacity:0}to{opacity:1}}@keyframes loading-spin{to{transform:rotate(360deg)}}@media(min-width:1700px){:root{--header-height:76px;--page-gutter:80px}.lesson-heading{padding:38px 0 24px}.interaction-stage{margin-top:22px}.interaction-scene{min-height:580px}.interaction-observation{padding:18px 0}.interaction-observation h2{font-size:28px}.classroom-footer{margin-top:20px;padding:8px 0}}@media(max-width:900px){:root{--page-gutter:20px}.brand-subject{display:none}.header-actions{gap:4px}.lesson-heading{padding-top:24px}h1{font-size:36px}.interaction-scene{overflow-x:auto;overscroll-behavior-x:contain;min-height:400px}.interaction-actions{flex-wrap:wrap}.interaction-observation h2{font-size:20px}.model-note{display:none}}@media(max-width:520px){.classroom-header{padding:0 16px;gap:8px}.classroom-brand strong{font-size:18px}.classroom-brand{gap:8px}.brand-mark{display:none}.header-actions{gap:2px}.header-actions button{font-size:14px;gap:5px;padding:8px 7px}.fullscreen-label{display:none}h1{font-size:34px}.lesson-eyebrow{font-size:16px}.course-menu{left:16px;right:16px;width:auto}.classroom-footer{gap:8px}.page-position{font-size:14px}.classroom-footer i{margin:0 8px}.classroom-footer .page-next{padding:8px 10px}.interaction-observation{align-items:center}.sql-statement{font-size:22px}}@media(prefers-reduced-motion:reduce){*,*:before,*:after{scroll-behavior:auto!important;animation-duration:0s!important;transition-duration:0s!important}}