:root{font-family:Inter,ui-sans-serif,system-ui,sans-serif;color:#152237;background:#e8eef5}*{box-sizing:border-box}html,body,#root{width:100%;min-width:960px;min-height:100%;margin:0}body{overflow:hidden}.classroom-shell{min-height:100vh;display:grid;grid-template-rows:62px 1fr 76px;background:#edf2f7}.classroom-header{display:flex;align-items:center;justify-content:space-between;padding:0 28px;color:#fff;background:#142e50;letter-spacing:.01em}.brand{display:flex;align-items:center;gap:10px;font-weight:700;font-size:17px}.brand b{color:#8fbfff;font-size:11px;letter-spacing:.12em;margin-left:4px}.brand-mark{display:grid;place-items:center;width:28px;height:28px;border-radius:50%;background:#e9603d;font-size:12px}.lesson-status{display:flex;gap:8px;align-items:center;color:#dbe8f7;font-size:13px}.record-dot{width:8px;height:8px;border-radius:50%;background:#ff6c5b}.timer{margin-left:12px;padding-left:12px;border-left:1px solid #4c6582;font-variant-numeric:tabular-nums}.class-label{color:#b9cbe0;font-size:13px}.classroom-main{display:grid;grid-template-columns:minmax(0,1fr) 340px;gap:18px;padding:20px 24px;min-height:0}.activity-panel,.media-panel{border:1px solid #d5e0eb;border-radius:10px;background:#fff;overflow:hidden;box-shadow:0 2px 8px #20364d0d}.activity-panel{padding:30px 42px;position:relative}.activity-topline{display:flex;justify-content:space-between;color:#64758a;font-size:13px;font-weight:650}.sync-badge{padding:4px 8px;border-radius:12px;color:#237b5d;background:#eaf8f1;font-size:11px}.progress{height:4px;margin:20px 0 44px;border-radius:4px;background:#e7edf3;overflow:hidden}.progress span{display:block;height:100%;background:#e9603d;transition:width 1s linear}.eyebrow{margin:0 0 12px;color:#e9603d;font-size:14px;font-weight:750;text-transform:uppercase;letter-spacing:.08em}.activity-panel h1{max-width:720px;margin:0 0 36px;color:#162a43;font-family:Georgia,serif;font-size:clamp(32px,3.6vw,54px);line-height:1.08;font-weight:500}.answer-grid{display:grid;gap:12px;max-width:680px}.answer{display:flex;align-items:center;gap:14px;padding:17px;border:1px solid #d8e1ea;border-radius:8px;color:#34465d;font-size:17px}.answer span{display:grid;place-items:center;width:27px;height:27px;border-radius:50%;color:#476079;background:#e9eff5;font-size:13px;font-weight:700}.classroom-note{position:absolute;right:42px;bottom:30px;left:42px;display:flex;justify-content:space-between;gap:20px;padding-top:18px;border-top:1px solid #e2e8ef;color:#65778b;font-size:12px}.classroom-note strong{color:#2c8061;white-space:nowrap}.classroom-note span{text-align:right}.media-panel{display:grid;grid-template-rows:50px 1fr;min-height:0;background:#192c43;border-color:#192c43}.media-heading{display:flex;justify-content:space-between;align-items:center;padding:0 16px;color:#e9f0f7;font-size:13px;font-weight:650}.live-pill{padding:3px 7px;border-radius:4px;color:#ffb6ad;background:#49333a;font-size:10px;letter-spacing:.08em}.media-grid{min-height:0}.media-grid rtk-grid{width:100%;height:100%}.participant-rail{display:flex;justify-content:space-between;align-items:center;padding:0 28px;border-top:1px solid #d6e0eb;background:#fff;color:#5d6f83;font-size:13px}.participant-rail strong{color:#26394f}.participant-chips{display:flex;gap:8px}.chip{padding:7px 11px;border-radius:16px;color:#4b6179;background:#edf3f8;font-size:12px}.chip.host{color:#7b3d31;background:#ffe9e3}.chip.muted{color:#7e8c9a}