.angle-lesson{--paper:#faeeeb;--ink:#276651;--muted:#7d8882;background:var(--paper);color:#315c50}
.angle-lesson header{height:68px;min-height:68px;padding:12px 26px;background:#ffffff38;border-color:#416b5515}
.angle-lesson header h1{font-size:21px;letter-spacing:2px}.angle-lesson .back{background:transparent;font-size:25px;padding:3px 10px}
.angle-lesson button{border-color:#7d8c7629;background:#fff8;border-radius:7px;padding:10px 19px;font-size:15px;min-height:42px;box-shadow:none}
.angle-lesson button,.angle-lesson a{touch-action:manipulation}.angle-lesson button:hover{transform:none;background:#fffc}.angle-lesson button.active,.angle-lesson button.primary{background:#188b80;border-color:#188b80;color:#fff}
.angle-lesson button:disabled{opacity:.38;cursor:default}.angle-lesson main{height:calc(100dvh - 68px);min-height:570px;overflow:visible}
.angle-tabs{display:flex;justify-content:center;gap:15px;padding:13px 15px 11px;flex-shrink:0}.angle-tabs button{padding:11px 27px;font-size:17px;border:0;background:transparent}
.drawing-area{position:relative;flex:1;min-height:310px;overflow:hidden}.drawing-area>svg{display:block;width:100%;height:100%;touch-action:none;user-select:none;-webkit-user-select:none}
.stage-heading{position:absolute;top:12px;left:12px;right:12px;text-align:center;pointer-events:none;z-index:1}.stage-heading h2{font-size:29px;font-weight:600;letter-spacing:4px;margin:0 0 9px}.stage-heading p{font-size:15px;margin:0;color:#7b8278;letter-spacing:1px}
.drawing-area .ray-hit{cursor:grab}.drawing-area .ray-hit:active{cursor:grabbing}.drawing-area .vertex-hit{cursor:move}.drawing-area [data-ruler-action=move]{cursor:grab}.drawing-area [data-ruler-action=rotate]{cursor:crosshair}
.ruler-tools{position:absolute;right:22px;bottom:8px;display:flex;gap:5px;align-items:center;background:#faeeebdd;padding:4px 7px;border-radius:8px;font-size:12px;color:#748277}.ruler-tools button{font-size:12px;padding:6px 10px;min-height:34px}.ruler-tools span{padding:0 5px}
.angle-lesson footer{flex-shrink:0;background:#ffffff14;padding:7px 14px 11px;border-top:1px solid #657d6910}.angle-tools{display:flex;align-items:center;justify-content:center;gap:10px;flex-wrap:wrap}.angle-tools i{width:1px;height:24px;background:#6c857133;margin:0 4px}.angle-tools button.quiet{background:transparent;color:#859082}
.angle-tools span{font-size:18px;vertical-align:middle}.angle-lesson #status{text-align:center;color:#8a877c;font-size:13px;line-height:1.6;margin:11px 0 0;min-height:21px}
.class-adjust{display:flex;align-items:center;justify-content:center;gap:16px;margin-top:13px;color:#7d897e;font-size:12px}.class-adjust input{width:min(360px,45vw);accent-color:#258574;min-width:100px}.class-adjust output{font-size:15px;color:#3c7060;width:40px;font-variant-numeric:tabular-nums}.part-tools{display:flex;justify-content:center;align-items:center;gap:8px;margin-top:10px;font-size:13px}.part-tools button{font-size:13px;padding:5px 13px;min-height:32px}
.angle-lesson dialog{border:1px solid #78978244;border-radius:17px;width:min(520px,90vw);padding:30px;color:#315b50;background:#fff9f3;box-shadow:0 18px 100px #263c4233}.angle-lesson dialog::backdrop{background:#183e393d;backdrop-filter:blur(3px)}.angle-lesson dialog h2{font-size:23px;margin:0 0 20px}.angle-lesson dialog p{font-size:16px;line-height:1.9}.angle-lesson dialog #closeHelp{position:absolute;right:12px;top:9px;border:0;background:transparent;font-size:25px}.angle-lesson dialog #gotIt{display:block;margin:24px auto 0;min-width:130px}
.battle-area{flex:1;min-height:370px;display:grid;grid-template-columns:1fr 1fr;gap:22px;padding:14px 35px;overflow:auto}.battle-card{border:1px solid #73999230;border-radius:18px;background:#fff6;padding:18px 20px;display:flex;flex-direction:column;align-items:center;min-width:0}.battle-card.red{border-color:#c4897a38}.battle-card h2{font-size:21px;margin:0;color:#3c817e;display:flex;width:100%;justify-content:space-between}.battle-card.red h2{color:#b86660}.battle-card h2 b{font-size:16px;font-weight:500}.battle-card .battle-hint{margin:10px 0 0;font-size:13px;color:#879184}.battle-card svg{width:100%;flex:1;min-height:230px;max-height:420px;touch-action:none;user-select:none}.battle-tools{display:flex;justify-content:center;gap:8px;flex-wrap:wrap}.battle-tools button{padding:7px 13px;font-size:13px;min-height:36px}.battle-answer{display:flex;align-items:center;gap:8px;margin-top:12px;font-size:15px}.battle-answer input{width:90px}.battle-feedback{font-size:13px;color:#8b857b;min-height:24px;margin:10px 0 0}.battle-feedback.success{color:#18856a}.battle-bottom{display:flex;gap:20px;align-items:center;justify-content:center}.battle-bottom span{font-size:14px;color:#7d887d}.angle-lesson [hidden]{display:none!important}
@media(max-width:850px){.angle-lesson header{padding:10px 14px}.angle-lesson header h1{font-size:18px}.angle-lesson .top-actions{gap:4px}.angle-lesson .top-actions button{padding:7px 11px;font-size:13px}.angle-tabs{gap:5px}.angle-tabs button{padding:10px 16px;font-size:15px}.angle-tools{gap:6px}.angle-tools button{padding:9px 14px;font-size:14px}.battle-area{padding:12px;gap:12px}.battle-card{padding:14px 10px}.stage-heading h2{font-size:25px}}
@media(max-width:600px){.angle-lesson header{height:61px;min-height:61px;padding:8px;gap:2px}.angle-lesson header h1{font-size:16px;letter-spacing:1px}.angle-lesson .top-actions button{padding:6px 8px;min-height:34px;font-size:12px}.angle-lesson .top-actions button:first-child{display:block}.angle-lesson #fullscreen{display:none}.angle-lesson main{height:auto;min-height:calc(100dvh - 61px)}.angle-tabs{gap:0;padding:8px 4px}.angle-tabs button{padding:9px 10px;font-size:14px;flex:1}.drawing-area{height:calc(100dvh - 273px);min-height:385px;flex:none}.stage-heading{top:8px}.stage-heading h2{font-size:22px;letter-spacing:2px}.stage-heading p{font-size:12px;letter-spacing:0}.ruler-tools{right:6px;bottom:3px}.angle-lesson footer{padding:8px 7px}.angle-tools{gap:5px}.angle-tools button{padding:8px 11px;font-size:13px;min-height:39px}.angle-tools i{margin:0;height:19px}.angle-lesson #status{font-size:12px;margin-top:8px;padding:0 8px}.part-tools{flex-wrap:wrap;gap:5px}.class-adjust{margin-top:8px;gap:9px}.battle-area{grid-template-columns:1fr;overflow:visible;padding:6px 12px 12px}.battle-card svg{height:280px;flex:none}.battle-bottom{flex-wrap:wrap;gap:7px}.angle-lesson dialog{padding:24px}.angle-lesson dialog p{font-size:14px}}
@media(max-height:600px) and (min-width:601px){.angle-lesson header{height:54px;min-height:54px}.angle-lesson main{height:calc(100dvh - 54px);min-height:410px}.angle-tabs{padding:5px}.angle-tabs button{padding:6px 18px;min-height:33px}.drawing-area{min-height:240px}.stage-heading{top:4px}.stage-heading h2{font-size:20px;margin-bottom:5px}.stage-heading p{font-size:12px}.angle-lesson #status{margin-top:5px;font-size:12px}.angle-lesson footer{padding:5px}.class-adjust{margin-top:4px}}