:root{color-scheme:light;--bg:#f4f5f1;--paper:#fffdf8;--white:#ffffff;--ink:#18394a;--muted:#546b71;--teal:#12675d;--teal-hover:#0a5149;--sage:#e9f1eb;--gold:#edb749;--line:#d9e1dc;--control:#71867d;--amber-bg:#fff3d6;--amber-ink:#74520b;--blue-bg:#eaf2f8;--blue-ink:#31576e;--green-bg:#e5f2e9;--green-ink:#236049;--error:#9d352b;font:16px/1.65 system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;color:var(--ink);background:var(--bg)}*{box-sizing:border-box}body{margin:0}a{color:var(--teal);text-underline-offset:4px}button,input,select,textarea{font:inherit}button{cursor:pointer;touch-action:manipulation;border:1px solid var(--control);border-radius:12px;padding:11px 17px;min-height:46px;background:var(--white);color:var(--ink);font-weight:600}button:hover{background:var(--sage);border-color:var(--teal)}button:disabled{opacity:.5;cursor:default}button:disabled:hover{background:var(--white);border-color:var(--control)}button:focus-visible,a:focus-visible,select:focus-visible,input:focus-visible,textarea:focus-visible,summary:focus-visible{outline:3px solid var(--teal);outline-offset:4px}h1,h2,h3,p{margin-top:0}h1,h2,h3{line-height:1.25;letter-spacing:-.035em}h1{font-size:clamp(1.65rem,3vw,2.2rem);font-weight:750}main{max-width:1240px;margin:auto;padding:32px 40px 26px}.site-header{background:var(--paper);border-bottom:1px solid var(--line)}.app-header{max-width:1320px;margin:auto;min-height:104px;padding:20px 40px;display:flex;align-items:center;justify-content:space-between;gap:22px}.brand{display:inline-flex;align-items:center;gap:14px;text-decoration:none;color:var(--ink);flex-shrink:0}.brand img{border-radius:16px;object-fit:cover}.brand strong{display:block;font-size:1.18rem;letter-spacing:-.03em}.brand small{display:block;font-size:.78rem;color:var(--muted);font-weight:500}.header-tools{display:flex;align-items:center;gap:10px}.header-subject{margin-right:14px;min-width:180px;font-size:.72rem;text-transform:uppercase;letter-spacing:.08em;color:var(--muted)}.header-subject select{margin-top:0;padding:4px 25px 4px 0;border:0;border-radius:0;background:transparent;min-height:30px;color:var(--ink);font-size:.92rem;text-transform:none;letter-spacing:normal;font-weight:650}.icon-button{display:inline-flex;align-items:center;justify-content:center;width:46px;height:46px;padding:10px;background:transparent;border:1px solid var(--line);border-radius:50%;color:var(--ink)}.welcome{display:flex;align-items:center;justify-content:space-between;gap:24px;margin:10px 0 28px}.welcome h1{margin:5px 0 10px}.eyebrow{font-size:.68rem;font-weight:750;letter-spacing:.14em;color:var(--teal);margin-bottom:10px}.welcome-copy{color:var(--muted);font-size:.95rem;margin:0}.welcome-mark{font:italic 1rem Georgia,serif;border-bottom:2px solid var(--gold);padding-bottom:5px;color:var(--muted);white-space:nowrap}.notice{white-space:pre-wrap;color:var(--ink);background:var(--sage);padding:14px 18px;border-radius:12px}.notice:empty,#message:empty{display:none}.workspace-bar{display:flex;align-items:end;justify-content:space-between;gap:24px;border-top:1px solid var(--line);padding:22px 0 14px}.theme-picker{width:clamp(220px,36%,380px);font-size:.72rem;color:var(--muted);letter-spacing:.04em}.theme-picker select{font-size:1rem;font-weight:650;letter-spacing:normal;background:transparent;border:0;border-bottom:1px solid var(--control);border-radius:0;padding-left:0}.view-tabs{display:flex;gap:5px;padding:5px;background:#e7ede7;border-radius:14px}.view-tabs button{display:flex;align-items:center;justify-content:center;gap:8px;min-height:44px;font-size:.85rem;border:1px solid transparent;border-radius:10px;padding:8px 13px;background:transparent;color:#46615c;white-space:nowrap}.view-tabs button[aria-pressed=true]{background:var(--white);color:var(--teal);border-color:var(--control);box-shadow:0 2px 4px #173c2e0a}.study-layout{display:grid;grid-template-columns:minmax(0,1fr) 260px;gap:34px}.study-main{min-width:0}.toolbar{display:flex;align-items:center;justify-content:space-between;gap:12px;flex-wrap:wrap}.card-toolbar{margin:8px 0 14px;min-height:40px;color:var(--muted);font-size:.83rem}.quiet-button{background:transparent;border:0;color:var(--muted);font-size:.82rem;padding:7px;min-height:40px}.learning-card{background:var(--paper);border:1px solid var(--line);border-radius:24px;padding:30px 34px 22px;box-shadow:0 10px 28px #18392f05;min-height:320px}.card-heading{display:flex;align-items:center;justify-content:space-between}.card-label{font-size:.65rem;font-weight:750;letter-spacing:.15em;color:var(--teal);background:var(--sage);padding:5px 11px;border-radius:6px}.card-dots{letter-spacing:3px;color:var(--muted)}#meta{font-size:.78rem;margin:22px 0 12px}#question{font-size:clamp(1.2rem,2.5vw,1.6rem);font-weight:650;line-height:1.55;letter-spacing:-.018em;white-space:pre-wrap;max-width:64ch;margin-bottom:26px;overflow-wrap:anywhere}.primary-button,#reveal{background:var(--teal);border-color:var(--teal);color:white;display:flex;align-items:center;justify-content:space-between;gap:32px;min-height:50px;min-width:235px;padding:12px 18px;font-size:.9rem}.primary-button:hover,#reveal:hover{background:var(--teal-hover)}#answer{white-space:pre-wrap;background:var(--sage);border-left:3px solid var(--teal);padding:18px 22px;border-radius:0 12px 12px 0;font-size:1.08rem;line-height:1.75;overflow-wrap:anywhere}#source{border-top:1px solid var(--line);padding-top:16px;margin:25px 0 0;font-size:.73rem;line-height:1.7}.muted{color:var(--muted)}.rating-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:10px;margin-top:16px}.rating-grid button{font-size:.85rem;display:flex;gap:9px;align-items:center;justify-content:center;min-height:50px}.rating-grid [data-score="1"]{background:var(--amber-bg);color:var(--amber-ink);border-color:#96773c}.rating-grid [data-score="2"]{background:var(--blue-bg);color:var(--blue-ink);border-color:#718b9a}.rating-grid [data-score="3"]{background:var(--green-bg);color:var(--green-ink);border-color:#668973}.rating-grid button:hover{box-shadow:inset 0 0 0 1px currentColor}.card-navigation{margin:12px 0 26px}.card-navigation button{font-size:.85rem;background:transparent;border-color:transparent;padding:9px 4px}.card-navigation button:hover{color:var(--teal);text-decoration:underline}.study-sidebar{padding-top:62px}.progress-panel{background:var(--sage);padding:23px 22px 18px;border-radius:18px}.progress-panel #stats{font-size:1.02rem;font-weight:650;margin:9px 0 14px}.progress-panel .muted{font-size:.76rem;margin:12px 0 0}.progress-track{height:6px;background:#ccdcd0;border-radius:9px;overflow:hidden}.progress-track span{display:block;width:0;height:100%;background:var(--teal);border-radius:9px}.selection-panel{border-top:1px solid var(--line);padding:20px 0;margin-top:22px}.selection-panel summary{font-size:.88rem;color:var(--ink);font-weight:650;cursor:pointer}.selection-panel label{font-size:.78rem;color:var(--muted);margin-top:16px}.small-brand{display:flex;align-items:center;gap:12px;border-top:1px solid var(--line);padding-top:20px;margin-top:0}.small-brand img{border-radius:12px}.small-brand p{font-size:.78rem;color:var(--muted);line-height:1.5;margin:0}.notes-panel{border-top:1px solid var(--line);padding:20px 0;color:var(--ink)}summary{cursor:pointer;font-weight:650;min-height:36px}.summary-hint{display:block;color:var(--muted);font-size:.77rem;font-weight:400;margin-left:17px}.drawing-tools{display:flex;gap:8px;flex-wrap:wrap;margin:16px 0 0}.drawing-tools button{font-size:.8rem;padding:7px 12px;min-height:40px}.drawing-tools button[aria-pressed=true]{background:var(--teal);color:white;border-color:var(--teal)}canvas{width:100%;background:var(--paper);touch-action:none;border:1px solid var(--control);border-radius:12px;margin-top:14px}.material-panel{background:var(--paper);border:1px solid var(--line);border-radius:20px;padding:20px;margin-top:16px}.material-panel label{font-size:.8rem;color:var(--muted)}iframe{display:block;width:100%;height:75vh;border:0;background:var(--paper);margin-top:16px}.app-main:not([data-view=cards]) .study-layout{grid-template-columns:minmax(0,1fr)}.app-main:not([data-view=cards]) .study-sidebar{display:none}.offline-panel{display:flex;align-items:center;justify-content:space-between;gap:20px;margin-top:26px;padding:22px 0 0;border-top:1px solid var(--line);color:var(--muted);font-size:.76rem}.offline-label{font-size:.8rem;font-weight:650;color:var(--ink)}.offline-panel p{margin:3px 0}.offline-panel button{font-size:.77rem;max-width:310px;min-height:44px;padding:9px 14px;background:transparent}label{display:block;font-weight:600}select,input,textarea{display:block;width:100%;padding:10px 12px;border:1px solid var(--control);border-radius:9px;background:var(--white);color:var(--ink);min-height:44px;margin-top:6px}input[type=checkbox]{display:inline;width:22px;height:22px;min-height:0;accent-color:var(--teal);vertical-align:middle;margin:0}.filters{display:flex;gap:14px;flex-wrap:wrap;margin:18px 0}.filters>label,.filters>button{flex:1;min-width:150px}.admin-page main{max-width:1280px}.admin-intro{margin:10px 0 30px}.admin-intro h1{margin-bottom:8px}.admin-page main>details,.panel{background:var(--paper);border:1px solid var(--line);padding:24px;border-radius:18px;margin:22px 0}.panel h2{font-size:1.2rem}.admin-page main>details>summary{font-size:1.1rem}.admin-page .toolbar{align-items:center}.back-link{font-size:.87rem;font-weight:650}.scroll{overflow:auto;margin:16px 0}table{width:100%;border-collapse:collapse;background:var(--paper)}th{font-size:.75rem;color:var(--muted);background:var(--sage);font-weight:700}td,th{text-align:left;padding:13px 12px;border-bottom:1px solid var(--line);vertical-align:middle}td{font-size:.85rem}td button{margin:3px;white-space:nowrap;font-size:.78rem}td input:not([type=checkbox]){min-width:100px}textarea{min-height:360px;font:14px/1.65 ui-monospace,monospace}.admin-page #import,.admin-page #publish{background:var(--teal);color:white;border-color:var(--teal)}.admin-page #card-preview details{border:1px solid var(--line);border-radius:10px;padding:14px;margin:12px 0}dialog{width:min(440px,calc(100% - 32px));max-height:90vh;overflow:auto;border:1px solid var(--line);border-radius:24px;padding:28px;color:var(--ink);background:var(--paper);box-shadow:0 24px 80px #12342b38}dialog::backdrop{background:#102f3e9e}.dialog-logo{display:block;border-radius:18px;margin-bottom:18px}dialog h2{font-size:1.5rem;margin:0}dialog label{margin:16px 0;font-size:.84rem}dialog #account{color:var(--muted);font-size:.9rem;margin-top:16px}dialog form button,dialog #logout{width:100%;margin-top:12px;background:var(--teal);border-color:var(--teal);color:white}#account-close{border:0;border-radius:50%;padding:8px;width:40px;min-height:40px;background:var(--sage)}#account-error{color:var(--error);font-size:.9rem}#account-error:empty{display:none}.skip-link{position:absolute;top:-100px;left:16px;padding:12px 18px;z-index:99;background:var(--paper)}.skip-link:focus{top:12px}.fraction{display:inline-flex;vertical-align:middle;flex-direction:column;text-align:center}.fraction span:first-child{border-bottom:1px solid}::selection{background:#d8ebd8;color:var(--ink)}[hidden]{display:none!important}
@media(max-width:1000px){.study-layout{grid-template-columns:minmax(0,1fr) 230px;gap:24px}main{padding:26px}.app-header{padding:18px 26px}.view-tabs button{padding:8px 10px;gap:6px}.workspace-bar{gap:20px}.welcome-mark{display:none}.learning-card{padding:26px}.view-tabs svg{display:none}}
@media(max-width:720px){main{padding:22px 18px}.app-header{padding:14px 18px;min-height:86px;gap:12px;flex-wrap:wrap}.brand img{width:44px;height:44px;border-radius:14px}.brand{gap:10px}.brand strong{font-size:1.02rem}.brand small{font-size:.68rem}.header-tools{gap:7px;flex-wrap:wrap;flex:1;justify-content:flex-end}.header-subject{min-width:130px;max-width:180px;margin-right:4px}.icon-button{width:42px;height:42px;padding:8px}.welcome{margin:8px 0 22px}.welcome h1{font-size:1.65rem}.welcome-copy{font-size:.86rem}.workspace-bar{display:block;padding-top:16px}.theme-picker{width:100%}.view-tabs{margin-top:20px;width:100%;justify-content:space-between}.view-tabs button{flex:1;padding:8px 6px;font-size:.8rem;gap:5px}.view-tabs svg{display:block;width:17px;height:17px}.study-layout{display:flex;flex-direction:column;gap:0}.study-sidebar{padding:0;order:-1;display:flex;align-items:start;gap:18px;margin:10px 0}.progress-panel{flex:1;min-width:0;background:transparent;padding:10px 0}.progress-panel .eyebrow,.progress-panel>.muted,.small-brand{display:none}.progress-panel #stats{font-size:.8rem;margin:0 0 8px}.selection-panel{flex:1;min-width:0;border:0;margin:0;padding:9px 0}.selection-panel summary{font-size:.8rem;text-align:right}.selection-panel[open] summary{text-align:left}.selection-panel label{font-size:.76rem}.card-toolbar{margin-top:0}.learning-card{border-radius:19px;padding:22px;min-height:300px}#question{font-size:1.25rem;line-height:1.6}#meta{margin-top:18px}#source{font-size:.7rem}.primary-button,#reveal{width:100%;min-width:0}.rating-grid{gap:7px}.rating-grid button{font-size:.76rem;padding:9px 6px;gap:5px}.offline-panel{align-items:start;flex-direction:column;gap:12px;margin-top:18px}.offline-panel button{max-width:none;width:100%}.admin-page main>details,.panel{padding:18px}.admin-page .app-header{flex-wrap:nowrap}.admin-page .brand small{display:none}}
@media(max-width:440px){.app-header{gap:10px}.header-tools{width:100%;flex-basis:100%;justify-content:flex-end}.header-subject{margin-right:auto;max-width:calc(100% - 110px);flex:1}.brand img{width:42px;height:42px}.brand strong{font-size:1.05rem}.brand small{display:none}.welcome h1{font-size:1.5rem}.view-tabs svg{display:none}.rating-grid button{flex-direction:column;gap:0}.admin-page .app-header{flex-wrap:wrap}.admin-page .back-link{margin-left:auto}}
@media(prefers-reduced-motion:no-preference){button,a{transition:background-color .15s,border-color .15s,color .15s}}
@media(forced-colors:active){.view-tabs button[aria-pressed=true]{border:2px solid Highlight}.progress-track{border:1px solid CanvasText}.progress-track span{background:Highlight}.learning-card{border:1px solid CanvasText}}