:root{--ink:#223b42;--muted:#5c6f74;--green:#238478;--green-soft:#e4f4ee;--yellow:#ffd561;--sky:#eaf5ff;--line:#cddfd9;--paper:#fffdf8;--red:#b43c3c;color-scheme:light;font-family:system-ui,-apple-system,PingFang SC,Microsoft YaHei,sans-serif}*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink)}button,input,select{font:inherit}.button,button{min-height:48px;min-width:48px;border:2px solid var(--line);border-radius:12px;background:white;color:var(--ink);font-size:16px;padding:10px 14px;cursor:pointer;touch-action:manipulation;text-decoration:none;display:inline-flex;align-items:center;justify-content:center;gap:6px}button:disabled{opacity:.45;cursor:default}a:focus-visible,button:focus-visible,input:focus-visible,select:focus-visible{outline:3px solid #c37800;outline-offset:3px}.primary{background:var(--green);border-color:var(--green);color:white;font-weight:700}.active,.selected{background:var(--green-soft);border-color:var(--green)}.full{width:100%;margin-top:10px}.text-button{background:none;border-color:transparent;padding:7px 10px;color:var(--green);font-size:15px}h1,h2,h3,p{margin-top:0}h1{font-size:25px;line-height:1.3;letter-spacing:-.4px}h2{font-size:21px;line-height:1.35}h3{font-size:18px}p{line-height:1.6}.muted,small{font-size:14px;color:var(--muted);line-height:1.55}.app-shell{max-width:1060px;margin:auto;padding:0 16px 24px}.site-header{justify-content:space-between;gap:12px;padding:16px 0;border-bottom:2px solid var(--line)}.brand,.site-header{display:flex;align-items:center}.brand{gap:9px;font-size:21px;font-weight:800;color:var(--ink);text-decoration:none}.brand small{display:block;font-size:13px;font-weight:500}.brand-mark{width:44px;height:44px;display:grid;place-content:center;border-radius:15px 15px 8px 15px;background:var(--yellow);font-size:33px;color:#334f45}.local-banner{padding:8px 12px;border:1px solid #e1c785;background:#fff4d8;margin-top:12px;font-size:14px;color:#745821}.welcome{padding:27px 0 22px;display:flex;flex-direction:column;gap:12px}.welcome p{margin-bottom:0}.profile-select label{font-size:14px;display:flex;align-items:center;gap:10px}.profile-select select{flex:1 1;min-width:0;max-width:310px}.tabs{display:flex;gap:7px;border-bottom:2px solid var(--line);padding-bottom:13px;margin-bottom:22px}.tabs button{flex:1 1;min-width:0;padding:9px 5px;font-size:16px;font-weight:650}.section-heading{display:flex;align-items:center;justify-content:space-between;gap:12px;margin:18px 0 13px}.section-heading h1,.section-heading h2{margin:0}.section-heading span{font-size:14px;color:var(--muted)}.question-grid{display:grid;grid-template-columns:1fr;grid-gap:18px;gap:18px}.question-card{border:2px solid var(--line);border-radius:17px;overflow:hidden;background:#fff}.question-open{width:100%;display:block;text-align:left;min-width:0;border:0;padding:12px;border-radius:0}.question-open img{display:block;object-fit:contain;width:100%;height:270px;background:#f5faf6;border-radius:8px}.question-open strong{font-size:19px;display:block;margin-top:12px;overflow-wrap:anywhere}.question-open>span{display:block;color:var(--muted);font-size:15px;margin-top:4px}.question-picture{position:relative}.page-number{position:absolute;left:8px;bottom:8px;padding:5px 10px;border-radius:8px;background:var(--yellow);color:#3c481d;font-size:14px;font-weight:650}.question-card>button:not(.question-open){margin:0 12px 10px}.lesson-section{margin-bottom:28px}.empty{padding:40px 15px;text-align:center;border:2px dashed var(--line);border-radius:18px;background:#f4faf6}.empty>span{font-size:42px;display:block;margin-bottom:13px}.empty p{color:var(--muted)}.empty button{margin:5px}.notice{padding:12px;background:#fff0ed;border:1px solid #e9c1b9;border-radius:10px;margin-bottom:16px}.notice p{margin-bottom:8px}footer{display:flex;flex-direction:column;align-items:flex-start;gap:7px;border-top:2px solid var(--line);margin-top:30px;padding-top:14px;font-size:14px;color:var(--muted)}.toast{bottom:30px;left:50%;transform:translateX(-50%);max-width:90vw;padding:13px 18px;background:#223e40;color:#fff;border-radius:10px;z-index:100;font-size:16px;box-shadow:0 4px 18px #20374030}.modal,.toast{position:fixed}.modal{inset:0;background:#153d435c;z-index:50;display:flex;align-items:center;justify-content:center;padding:14px}.modal-card{background:white;border-radius:20px;border:2px solid var(--line);width:100%;max-width:540px;padding:24px 18px;max-height:calc(100dvh - 28px);overflow:auto;position:relative}.modal-card.wide{max-width:800px}.close{position:absolute;right:10px;top:8px;background:#fff;font-size:26px;border-color:transparent}.modal-card h2{padding-right:40px;margin-bottom:14px}.admin-panel label,.modal-card label{display:flex;flex-direction:column;gap:7px;font-size:16px;margin-bottom:14px}input:not([type=range]),select{font-size:16px;border:2px solid var(--line);padding:11px 10px;min-height:48px;border-radius:8px;background:white;max-width:100%;color:var(--ink)}input[type=file]{width:100%;padding:10px;font-size:14px}input::-webkit-file-upload-button{padding:9px 12px;border:0;background:var(--green-soft);color:var(--ink);margin-right:9px;border-radius:6px;font:inherit}input::file-selector-button{padding:9px 12px;border:0;background:var(--green-soft);color:var(--ink);margin-right:9px;border-radius:6px;font:inherit}.profile-symbols{display:flex;gap:8px;margin-bottom:20px}.profile-symbols button{font-size:28px}.photo-list{display:flex;gap:9px;flex-wrap:wrap;margin-bottom:12px}.photo-list>div{display:flex;flex-direction:column;align-items:center}.photo-list img,.teacher-preview{width:90px;height:90px;object-fit:cover;border-radius:15px;border:2px solid var(--line)}.photo-list button{font-size:14px;min-height:40px;border-color:transparent}.export-preview{width:100%;max-height:48dvh;object-fit:contain;background:#f3faf6}.celebration{text-align:center}.celebration h2{padding:0}.star-reward{font-size:39px;margin:27px 0 20px;animation:reward .6s ease-out}.admin{padding-top:15px}.admin-panel{border:1px solid var(--line);padding:18px 14px;border-radius:12px;background:white;margin:20px 0}.form-row{display:flex;flex-direction:column;gap:0}.form-row label{flex:1 1;min-width:0}.upload-box{padding:16px;background:#f0f8f4;border:2px dashed #97bfb0;border-radius:10px}.upload-grid{display:grid;grid-template-columns:1fr 1fr;grid-gap:12px;gap:12px;margin-bottom:18px}.upload-item{min-width:0;border:1px solid var(--line);padding:7px;border-radius:8px}.upload-item img{width:100%;height:130px;object-fit:contain}.upload-item span{font-size:14px;display:block;overflow-wrap:anywhere;margin:7px 0}.upload-item>div{display:flex;flex-wrap:wrap;gap:3px}.upload-item button{padding:6px;min-height:44px;font-size:14px}.admin-lesson{display:flex;flex-direction:column;gap:9px;padding:15px 0;border-bottom:1px solid var(--line);margin-bottom:12px}.admin-lesson strong{font-size:18px}.admin-lesson p{font-size:14px;color:var(--muted);margin:4px 0}.admin-lesson button{margin-right:6px}.preview-page{margin-bottom:20px}.preview-page img{width:100%;height:auto}.board-screen{height:100vh;height:100dvh;display:flex;flex-direction:column;overflow:hidden;padding-top:env(safe-area-inset-top);background:#fff}.board-head{display:flex;gap:7px;align-items:center;padding:8px;border-bottom:2px solid var(--line);flex:none}.board-head>div{flex:1 1;min-width:0}.board-head strong{display:block;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;font-size:16px}.board-head small{font-size:13px;display:block}.board-head button{padding:8px;font-size:15px}.companions{display:flex;justify-content:center;align-items:center;gap:8px;padding:5px 8px;background:#fff8de;position:relative;min-height:80px}.companion{display:flex;flex-direction:row;gap:6px;border-color:transparent;background:transparent;padding:3px;max-width:190px}.companion img{width:54px;height:54px;object-fit:cover;border:3px solid #fff;border-radius:50%;box-shadow:0 0 0 2px #eabf4e}.companion span{font-size:13px;line-height:1.3;max-width:50px}.close-companion{margin-left:0;min-width:32px;padding:2px;border:0;background:transparent;font-size:22px}.view-tools{display:flex;align-items:center;gap:5px;padding:4px 8px;flex:none}.view-tools span{font-size:14px;min-width:44px;text-align:center}.view-tools button{font-size:14px;padding:8px;min-height:44px}.view-tools button:last-child{margin-left:auto}.drawing-area{flex:1 1;min-height:80px;position:relative;overflow:hidden;touch-action:none;-moz-user-select:none;user-select:none;-webkit-user-select:none;background:#e8f1f2}.drawing-paper{position:absolute;left:0;top:0;transform-origin:0 0;background:white;box-shadow:0 2px 10px #1c3c3b24}.drawing-paper canvas,.drawing-paper img{width:100%;height:100%;position:absolute;inset:0;pointer-events:none}.board-toolbar{display:flex;gap:4px;padding:7px 6px 2px;flex:none;border-top:2px solid var(--line)}.board-toolbar button{flex:1 1;min-width:0;padding:5px 1px;font-size:14px;display:flex;flex-direction:column;gap:0}.board-toolbar button span{font-size:26px;line-height:29px}.board-foot{text-align:center;color:var(--muted);font-size:13px;padding:5px 6px calc(6px + env(safe-area-inset-bottom));flex:none}.extra-tools{display:flex;align-items:center;flex-wrap:wrap;gap:5px;padding:7px;background:#f4faf6;flex:none}.extra-tools button{min-height:44px;font-size:14px;padding:7px}.extra-tools label{font-size:14px;display:flex;align-items:center;gap:5px}.extra-tools input{width:90px;accent-color:var(--green);height:44px}.extra-tools .swatch{border:3px solid #fff;border-radius:50%;min-width:36px;width:36px;min-height:36px;height:36px;box-shadow:0 0 0 1px #879d97}.board-screen .toast{bottom:130px}@keyframes reward{0%{transform:scale(.75);opacity:.3}to{transform:scale(1);opacity:1}}@media(min-width:540px){.question-grid{grid-template-columns:1fr 1fr}.form-row{flex-direction:row;gap:14px}.admin-lesson,.welcome{flex-direction:row;align-items:center;justify-content:space-between}.profile-select label{flex-direction:column;align-items:flex-start}h1{font-size:29px}.site-header{padding:20px 0}.board-toolbar{justify-content:center}.board-toolbar button{max-width:130px}.board-head{padding:10px 20px}.board-head strong{font-size:19px}.view-tools{padding-left:20px;padding-right:20px}footer{flex-direction:row;align-items:center;justify-content:space-between}.upload-grid{grid-template-columns:1fr 1fr 1fr 1fr}}@media(prefers-reduced-motion:reduce){.star-reward{animation:none}}@media(max-height:550px){.companions{min-height:60px}.companion img{width:42px;height:42px}.board-toolbar button{flex-direction:row}.board-foot{display:none}.board-head{padding:3px 8px}}