.tetromino-lesson{--paper:#e2eafa;--ink:#325674;background:var(--paper);color:var(--ink)}.tetromino-lesson header{height:64px;min-height:64px;background:#ffffff4a;border-color:#7293b023;padding:11px 25px}.tetromino-lesson h1{font-size:21px;letter-spacing:2px}.tetromino-lesson .back{background:transparent;padding:4px 10px;font-size:24px}.tetromino-lesson button{min-height:40px;padding:8px 17px;border-radius:8px;border-color:#7190ab35;background:#ffffff88;font-size:14px;touch-action:manipulation}.tetromino-lesson button:hover{transform:none;background:#fffffff0}.tetromino-lesson button:disabled{opacity:.36;cursor:default}.tetromino-lesson button.active,.tetromino-lesson button.primary{background:#238eaf;color:#fff;border-color:#238eaf}.tetromino-lesson main{height:calc(100dvh - 64px);min-height:660px;overflow:visible}.lesson-tabs{display:flex;justify-content:center;gap:20px;padding:10px 15px 6px;flex-shrink:0}.lesson-tabs button{border:0;background:transparent;padding:10px 30px;font-size:17px}.activity-bar{display:flex;justify-content:center;align-items:center;gap:14px;padding:4px 20px 10px;min-height:47px;flex-shrink:0;font-size:13px;color:#6c849d}.activity-bar p{margin:0;line-height:1.65}.activity-bar button{font-size:12px;padding:5px 13px;min-height:32px}.activity-bar label{gap:7px}.activity-bar select{font-size:13px;padding:6px 9px;border-color:#b3c4d8;background:#ffffff83}.activity-bar .own-toggle{font-size:12px}.own-toggle input{accent-color:#258bab;width:16px;height:16px}.activity-bar b{font-size:14px;margin-left:5px;color:#228da8}.paper-stage{position:relative;flex:1;min-height:300px;overflow:hidden}.paper-stage>svg{display:block;width:100%;height:100%;touch-action:none;user-select:none;-webkit-user-select:none;outline-offset:-3px}.paper-stage [data-piece-id]{cursor:grab}.paper-stage [data-piece-id]:active{cursor:grabbing}.paper-stage [data-cell]{cursor:crosshair}.paper-stage.panning svg,.paper-stage.panning [data-cell]{cursor:grab}.stage-message{position:absolute;left:50%;top:8px;transform:translateX(-50%);color:#765375;background:#fffc;border:1px solid #ffffff;border-radius:30px;padding:10px 23px;font-size:15px;box-shadow:0 4px 20px #45648b0d;text-align:center;max-width:88%;pointer-events:none;opacity:0;transition:opacity .15s}.stage-message.visible{opacity:1}.stage-message.success{color:#248269}.stage-info{position:absolute;top:11px;left:22px;font-size:13px;color:#6d879f;pointer-events:none}.paper-navigation{position:absolute;right:17px;bottom:9px;display:flex;gap:5px;background:#e2eafad9;border-radius:9px;padding:4px}.paper-navigation button{padding:5px 10px;min-height:31px;font-size:12px}.palette-row{display:flex;align-items:center;justify-content:center;gap:12px;padding:7px 17px;background:#ffffff20;flex-shrink:0;flex-wrap:wrap}.palette-label{font-size:13px;line-height:1.6;color:#6887a0}.palette-label small{font-size:10px;color:#8a9cae}#pieces{display:flex;gap:14px;align-items:center}#pieces button{border:1px solid transparent;background:transparent;min-width:70px;padding:5px;min-height:63px;touch-action:none}#pieces button:hover,#pieces button.active{background:#ffffff6b;border-color:#61a9c283;color:inherit}#pieces svg{width:75px;height:52px;display:block;pointer-events:none}.palette-row>button{font-size:12px;padding:7px 11px;min-height:35px}.tetromino-lesson footer{padding:8px 20px 10px;border-top:1px solid #648cb11c;flex-shrink:0}.piece-actions{display:flex;justify-content:center;gap:24px}.piece-actions button{width:min(25vw,270px);border-radius:30px;border-width:2px;font-size:18px;padding:10px 18px;min-height:49px;background:#ffffff38;box-shadow:0 3px 0 var(--edge);border-color:var(--edge);color:var(--tone);display:flex;gap:12px;justify-content:center;align-items:center}.piece-actions svg{width:25px;height:25px;stroke:currentColor;fill:none;stroke-width:1.7;stroke-linecap:round;stroke-linejoin:round}.rotate-action{--edge:#d7b750;--tone:#9a7728}.flip-action{--edge:#459bb8;--tone:#2b7398}.delete-action{--edge:#bf799d;--tone:#9c557e}.secondary-actions{display:flex;justify-content:center;gap:12px;margin-top:11px}.secondary-actions button{background:transparent;border:0;font-size:12px;color:#748aa2;padding:3px 8px;min-height:24px}.secondary-actions button:hover{background:#ffffff65}.tetromino-lesson #status{font-size:12px;line-height:1.6;color:#7d91a7;text-align:center;min-height:19px;margin:7px 0 0}.tetromino-lesson dialog{border:1px solid #b7c8e0;border-radius:16px;max-width:min(580px,92vw);padding:29px;color:#365871;background:#f5f8ff;box-shadow:0 20px 100px #30506844}.tetromino-lesson dialog::backdrop{background:#2e49674d;backdrop-filter:blur(3px)}.tetromino-lesson dialog h2{font-size:23px;margin:0 0 16px}.tetromino-lesson dialog p{font-size:15px;line-height:1.9}.tetromino-lesson dialog .primary{display:block;margin:22px auto 0;min-width:130px}.dialog-close{position:absolute;right:9px;top:7px;background:transparent!important;border:0!important;font-size:24px!important}.found-gallery{display:flex;gap:15px;flex-wrap:wrap;justify-content:center}.found-item{text-align:center;font-size:13px;padding:14px 10px}.found-item svg{display:block;width:110px;height:100px;margin-bottom:7px}.tetromino-lesson [hidden]{display:none!important}
@media(max-width:900px){.tetromino-lesson header{padding:10px 14px}.tetromino-lesson .top-actions{gap:5px}.tetromino-lesson .top-actions button{padding:6px 10px;font-size:12px}.lesson-tabs{gap:8px}.lesson-tabs button{font-size:15px;padding:9px 23px}.activity-bar{gap:9px;padding-inline:10px;flex-wrap:wrap}.activity-bar span{font-size:12px}.palette-row{gap:7px}#pieces{gap:4px}#pieces button{min-width:60px}#pieces svg{width:60px;height:48px}.piece-actions{gap:15px}.piece-actions button{width:27vw;font-size:16px;min-height:44px}.piece-actions svg{width:22px;height:22px}.stage-message{font-size:13px}}
@media(max-width:600px){.tetromino-lesson header{height:57px;min-height:57px;padding:7px 8px;gap:3px}.tetromino-lesson h1{font-size:16px;letter-spacing:1px}.tetromino-lesson .top-actions{gap:2px}.tetromino-lesson .top-actions button{min-height:32px;font-size:11px;padding:5px 7px}.tetromino-lesson .top-actions button:first-child{display:block}.tetromino-lesson #fullscreen{display:none}.tetromino-lesson main{min-height:calc(100dvh - 57px);height:auto}.lesson-tabs{padding:8px 6px 4px;gap:2px}.lesson-tabs button{flex:1;padding:9px 4px;font-size:14px}.activity-bar{font-size:12px;gap:6px;padding:6px 10px;min-height:48px}.activity-bar p{flex:1}.activity-bar label{font-size:12px}.activity-bar select{font-size:12px;max-width:128px}.activity-bar .own-toggle{margin-left:0}.paper-stage{height:calc(100dvh - 307px);min-height:410px;flex:none}.tetromino-lesson.puzzle-mode .paper-stage{height:calc(100dvh - 408px);min-height:345px}.stage-info{top:6px;left:12px;font-size:11px}.stage-message{top:27px;padding:8px 13px;border-radius:12px;font-size:12px;max-width:94%;width:max-content}.paper-navigation{right:6px;bottom:6px;padding:3px;gap:3px}.paper-navigation button{padding:5px 8px;min-height:30px;font-size:11px}.palette-row{padding:5px 6px;gap:3px}.palette-label{display:none}#pieces{width:100%;justify-content:center;gap:8px}#pieces button{min-width:54px;min-height:57px;padding:4px}#pieces svg{width:54px;height:43px}.palette-row>button{font-size:11px;min-height:29px;padding:4px 10px}.tetromino-lesson footer{padding:8px 8px}.piece-actions{gap:10px}.piece-actions button{width:29vw;min-height:42px;font-size:15px;padding:8px 10px;gap:6px}.piece-actions svg{width:20px;height:20px}.secondary-actions{margin-top:8px;gap:5px}.secondary-actions button{font-size:11px;padding:3px 8px}.tetromino-lesson #status{font-size:11px;margin-top:4px}.tetromino-lesson dialog{padding:24px;max-height:86dvh;overflow:auto}.tetromino-lesson dialog p{font-size:13px}.tetromino-lesson dialog h2{font-size:19px}}
@media(max-height:600px) and (min-width:601px){.tetromino-lesson header{height:52px;min-height:52px}.tetromino-lesson main{height:auto;min-height:calc(100dvh - 52px)}.lesson-tabs{padding:4px}.lesson-tabs button{padding:5px 18px;min-height:32px}.activity-bar{min-height:36px;padding-block:4px}.paper-stage{height:320px;flex:none}.piece-actions button{min-height:38px;padding:6px 15px}.tetromino-lesson footer{padding:6px}.secondary-actions{margin-top:6px}}
@media(prefers-reduced-motion:reduce){.stage-message{transition:none}}