/* Study Buddy: app styles on top of the Zec Labs kit (zl.css). Colours come from kit tokens only. */

[hidden]{display:none!important}
.sb-grow{flex:1}
.sb-muted{color:var(--muted);font-size:14px}
.sb-center{text-align:center}
.sb-link{border:0;background:none;padding:0;color:var(--accent-ink);font:inherit;font-weight:600;cursor:pointer;text-decoration:underline;text-underline-offset:2px}
kbd{display:inline-flex;align-items:center;justify-content:center;min-width:22px;height:22px;padding:0 6px;border:1px solid var(--line-strong);border-bottom-width:2px;border-radius:6px;background:var(--surface);color:var(--ink-2);font:600 12px/1 var(--font)}
.sb-kbd-hint{font-size:13px;color:var(--muted);margin:0}
.sb-kbd-hint kbd{margin:0 1px}

/* ---------- app bar ---------- */
.sb-app .zl-appbar{gap:10px;padding:12px 16px 12px 20px}
.zl-appbar-title .zl-dot{transition:background .3s}
#modeDot[data-mode="key"]{background:var(--accent);box-shadow:0 0 0 3px var(--accent-soft)}
#modeDot[data-mode="demo"]{background:var(--warn);box-shadow:0 0 0 3px color-mix(in oklab,var(--warn) 20%,transparent)}
#modeDot[data-mode="checking"]{background:var(--faint);box-shadow:none}
.zl-appbar-status[data-state="saved"]{color:var(--good)}
.zl-appbar-status[data-state="busy"]{color:var(--accent-ink)}
.sb-mode{display:inline-flex;align-items:center;gap:8px;min-height:36px;padding:0 14px;border-radius:999px;border:1px solid var(--line);background:var(--surface);font-size:14px;font-weight:600;color:var(--ink);cursor:pointer;transition:border-color .15s,background .15s}
.sb-mode:hover{border-color:var(--line-strong)}
.sb-mode-dot{width:8px;height:8px;border-radius:50%;background:var(--faint);flex:none}
[data-mode="hosted"] > .sb-mode-dot{background:var(--good)}
[data-mode="key"] > .sb-mode-dot{background:var(--accent)}
[data-mode="demo"] > .sb-mode-dot{background:var(--warn)}
@media (prefers-reduced-motion:no-preference){[data-mode="checking"] > .sb-mode-dot{animation:sb-pulse 1.2s ease-in-out infinite}}
@keyframes sb-pulse{50%{opacity:.3}}

/* ---------- workspace ---------- */
.sb-work{display:grid;grid-template-columns:minmax(320px,380px) minmax(0,1fr)}
.sb-compose{display:flex;flex-direction:column;gap:20px;padding:24px;border-right:1px solid var(--line);background:color-mix(in oklab,var(--surface-2) 35%,var(--surface));min-width:0}
.sb-pane-head{display:flex;align-items:center;justify-content:space-between}
.sb-pane-head h2{margin:0;font-size:21px;font-weight:700;letter-spacing:-.025em}
.sb-drop{position:relative;border-radius:var(--r-sm)}
.sb-notes{min-height:320px;font-size:16px;line-height:1.55;display:block}
.sb-drop-overlay{position:absolute;inset:0;border-radius:var(--r-sm);border:2px dashed var(--accent);background:color-mix(in oklab,var(--accent) 10%,var(--surface));display:flex;flex-direction:column;align-items:center;justify-content:center;gap:4px;color:var(--accent-ink);opacity:0;pointer-events:none;transition:opacity .15s}
.sb-drop-overlay svg{width:32px;height:32px;margin-bottom:6px}
.sb-drop-overlay span{font-size:14px;color:var(--muted)}
.sb-drop[data-over] .sb-drop-overlay{opacity:1}
.sb-notes-meta{display:flex;justify-content:space-between;align-items:baseline;gap:12px}
.zl-hint[data-state="busy"]{color:var(--accent-ink);font-weight:500}
.sb-count{font-size:13px;color:var(--muted);white-space:nowrap;font-variant-numeric:tabular-nums}
.sb-count[data-state="near"]{color:var(--warn)}
.sb-count[data-state="over"]{color:var(--bad);font-weight:600}
.sb-inline-error{display:flex;flex-direction:column;align-items:flex-start;gap:4px}
.sb-inline-error .zl-btn{padding:0 10px;margin-left:-10px}
.sb-file-row{display:flex;flex-direction:column;align-items:flex-start;gap:10px}
.sb-file-chip{display:flex;align-items:center;gap:12px;width:100%;padding:8px 8px 8px 10px;border:1px solid var(--line);border-radius:var(--r-md);background:var(--surface)}
.sb-file-icon{width:36px;height:36px;border-radius:9px;display:grid;place-items:center;background:var(--accent-soft);color:var(--accent-ink);font-size:11px;font-weight:700;letter-spacing:.02em;flex:none}
.sb-file-text{display:flex;flex-direction:column;min-width:0;flex:1}
.sb-file-text b{font-size:14px;font-weight:600;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.sb-file-text span{font-size:13px;color:var(--muted)}
.sb-x{width:36px;height:36px;border:0;border-radius:50%;background:transparent;color:var(--muted);display:grid;place-items:center;cursor:pointer;flex:none}
.sb-x:hover{background:var(--surface-2);color:var(--ink)}
.sb-x svg{width:16px;height:16px}
.sb-go-wrap{display:flex;flex-direction:column;gap:10px;margin-top:4px}
.sb-go{width:100%}
.sb-go[aria-busy="true"] svg{animation:sb-spin 1.2s linear infinite}
.sb-go-hint{margin:0;text-align:center}

/* ---------- study pane ---------- */
.sb-study{padding:28px 36px 36px;min-width:0;min-height:640px}
.sb-set-head{display:flex;align-items:flex-start;justify-content:space-between;gap:16px}
.sb-set-titles{min-width:0}
.sb-set-head h2{margin:0;font-size:30px;line-height:1.15;font-weight:700;letter-spacing:-.035em;text-wrap:balance}
.sb-set-meta{margin:8px 0 0;color:var(--muted);font-size:14px;display:flex;align-items:center;gap:8px;flex-wrap:wrap}
.sb-tabs{display:flex;width:100%;margin:22px 0 28px}
.sb-tabs button{flex:1 0 auto;display:inline-flex;align-items:center;justify-content:center;gap:6px}
.sb-tab-n{font-size:12px;font-weight:600;color:var(--muted);font-variant-numeric:tabular-nums;display:inline-flex;align-items:center;gap:4px}
.sb-tab-n:empty{display:none}
.sb-tl-short{display:none}
.sb-tab-n[data-due="1"]{color:var(--accent-ink)}
.sb-due-dot{width:6px;height:6px;border-radius:50%;background:var(--accent)}
.sb-panel:focus{outline:none}
.sb-panel:focus-visible{outline:3px solid color-mix(in oklab,var(--accent) 50%,transparent);outline-offset:6px;border-radius:12px}
@media (prefers-reduced-motion:no-preference){.sb-panel:not([hidden]){animation:sb-fade .28s var(--ease)}}
@keyframes sb-fade{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:none}}
.sb-toolbar{display:flex;align-items:center;gap:8px;flex-wrap:wrap;margin-bottom:20px;min-height:44px}
.sb-toolbar .zl-btn-ghost svg{width:16px;height:16px}

/* summary */
.sb-overview{font-size:19px;line-height:1.5;color:var(--ink);letter-spacing:-.014em;margin:0 0 28px;max-width:64ch;text-wrap:pretty}
.sb-sections{display:grid}
.sb-sec{display:grid;grid-template-columns:210px minmax(0,1fr);gap:24px;padding:20px 0;border-top:1px solid var(--line)}
.sb-sec h3{margin:0;font-size:16px;line-height:1.35;font-weight:600;letter-spacing:-.012em;display:flex;gap:10px;align-items:flex-start}
.sb-sec-n{width:24px;height:24px;border-radius:50%;background:var(--accent-soft);color:var(--accent-ink);font-size:12px;font-weight:700;display:grid;place-items:center;flex:none;margin-top:-1px}
.sb-sec ul{margin:0;padding:0;list-style:none;display:grid;gap:10px}
.sb-sec li{position:relative;padding-left:18px;color:var(--ink-2);font-size:16px;line-height:1.55}
.sb-sec li::before{content:"";position:absolute;left:2px;top:.68em;width:6px;height:6px;border-radius:50%;background:var(--accent)}

/* key terms */
.sb-search{position:relative;flex:1 1 240px;max-width:380px}
.sb-search svg{position:absolute;left:14px;top:50%;width:18px;height:18px;transform:translateY(-50%);color:var(--muted);pointer-events:none}
.sb-search .zl-input{padding-left:42px;border-radius:999px}
.sb-terms{margin:0}
.sb-term{display:grid;grid-template-columns:220px minmax(0,1fr);gap:24px;padding:16px 0;border-top:1px solid var(--line)}
.sb-term dt{font-weight:600;font-size:16px;letter-spacing:-.012em}
.sb-term dd{margin:0;color:var(--ink-2);font-size:16px;line-height:1.55}
.sb-term-empty svg{width:36px;height:36px}

/* KaTeX sizing inside UI text */
.katex{font-size:1.06em}
.katex-display{margin:.4em 0;overflow-x:auto;overflow-y:hidden;padding:2px 0}
.tex{font-style:italic}

/* ---------- quiz ---------- */
.sb-quiz{max-width:760px}
.sb-quiz-top{display:flex;align-items:center;gap:8px}
.sb-quiz-top b{color:var(--ink)}
.sb-qbar{display:flex;gap:4px;margin-top:12px}
.sb-qbar span{flex:1;height:4px;border-radius:2px;background:var(--line);transition:background .25s}
.sb-qbar span[data-state="now"]{background:var(--ink-2)}
.sb-qbar span[data-state="good"]{background:var(--good)}
.sb-qbar span[data-state="bad"]{background:var(--bad)}
.sb-q{font-size:24px;line-height:1.32;font-weight:600;letter-spacing:-.022em;margin:28px 0 22px;text-wrap:pretty}
.sb-opts{display:grid;gap:10px}
.sb-opt{display:grid;grid-template-columns:32px minmax(0,1fr) 22px;align-items:center;gap:14px;min-height:60px;padding:12px 16px;border-radius:var(--r-md);border:1px solid var(--line-strong);background:var(--surface);color:var(--ink);text-align:left;font-size:17px;cursor:pointer;transition:border-color .15s,background .15s,opacity .2s,transform .1s}
.sb-opt:hover:not([disabled]){border-color:var(--accent-line);background:color-mix(in oklab,var(--accent) 5%,var(--surface))}
.sb-opt:active:not([disabled]){transform:scale(.99)}
.sb-opt[disabled]{cursor:default}
.sb-key{width:32px;height:32px;border-radius:9px;background:var(--surface-2);border:1px solid var(--line);display:grid;place-items:center;font-size:14px;font-weight:700;color:var(--muted);transition:background .2s,color .2s,border-color .2s}
.sb-opt-mark svg{width:20px;height:20px}
.sb-opt.is-correct{border-color:var(--good);background:color-mix(in oklab,var(--good) 10%,var(--surface))}
.sb-opt.is-correct .sb-key{background:var(--good);border-color:var(--good);color:#fff}
.sb-opt.is-correct .sb-opt-mark{color:var(--good)}
.sb-opt.is-wrong{border-color:var(--bad);background:color-mix(in oklab,var(--bad) 8%,var(--surface))}
.sb-opt.is-wrong .sb-key{background:var(--bad);border-color:var(--bad);color:#fff}
.sb-opt.is-wrong .sb-opt-mark{color:var(--bad)}
.sb-opt.is-dim{opacity:.5}
@media (prefers-reduced-motion:no-preference){.sb-opt.pop{animation:sb-pop .32s var(--ease)}}
@keyframes sb-pop{40%{transform:scale(1.015)}}
.sb-feedback:empty{display:none}
.sb-feedback{margin-top:18px;padding:16px 18px;border-radius:var(--r-md);background:var(--surface-2)}
.sb-verdict{font-weight:700;font-size:16px}
.sb-verdict.good{color:var(--good)}
.sb-verdict.bad{color:var(--bad)}
.sb-feedback p{margin:6px 0 0;color:var(--ink-2);font-size:16px;line-height:1.55}
.sb-quiz-foot{display:flex;align-items:center;gap:12px;margin-top:22px;min-height:44px;flex-wrap:wrap}

.sb-result{display:flex;align-items:center;gap:44px;padding:8px 0 8px}
.sb-ring-wrap{position:relative;width:184px;height:184px;flex:none}
.sb-ring{width:100%;height:100%;transform:rotate(-90deg)}
.sb-ring circle{fill:none;stroke-width:12}
.sb-ring .trk{stroke:var(--line)}
.sb-ring .val{stroke:var(--good);stroke-linecap:round;transition:stroke-dashoffset 1.1s var(--ease)}
.sb-ring[data-tone="mid"] .val{stroke:var(--accent)}
.sb-ring[data-tone="low"] .val{stroke:var(--warn)}
.sb-ring-label{position:absolute;inset:0;display:flex;flex-direction:column;align-items:center;justify-content:center}
.sb-ring-label b{font-size:46px;font-weight:700;letter-spacing:-.045em;line-height:1}
.sb-ring-label small{font-size:22px;color:var(--muted);font-weight:600;letter-spacing:-.02em}
.sb-ring-label span{font-size:14px;color:var(--muted);margin-top:4px;font-weight:500}
.sb-result-text h3{margin:0;font-size:30px;font-weight:700;letter-spacing:-.035em;line-height:1.15}
.sb-result-text p{margin:8px 0 0;color:var(--muted);font-size:17px}
.sb-result-actions{display:flex;flex-wrap:wrap;gap:10px;margin-top:22px}
.sb-review{margin-top:32px;border-top:1px solid var(--line);padding-top:24px}
.sb-review h4{margin:0 0 4px;font-size:17px;font-weight:600}
.sb-review-item{padding:18px 0;border-bottom:1px solid var(--line)}
.sb-review-item:last-child{border-bottom:0}
.sb-review-item h5{margin:0 0 10px;font-size:17px;font-weight:600;line-height:1.4;letter-spacing:-.012em}
.sb-ans{display:flex;align-items:flex-start;gap:10px;margin:6px 0;font-size:16px}
.sb-ans svg{width:18px;height:18px;flex:none;margin-top:3px}
.sb-ans.bad{color:var(--bad)}
.sb-ans.good{color:var(--good)}
.sb-ans span{color:var(--ink)}
.sb-review-why{margin:10px 0 0;color:var(--ink-2);font-size:15px;line-height:1.55;padding:12px 14px;border-radius:var(--r-sm);background:var(--surface-2)}

/* ---------- flashcards ---------- */
.sb-cards-top{display:flex;align-items:center;gap:10px;flex-wrap:wrap;margin-bottom:18px}
.sb-seg-n{font-size:12px;color:var(--muted);margin-left:4px}
[aria-pressed="true"] > .sb-seg-n{color:var(--accent-ink)}
.sb-deck{margin-bottom:24px}
.sb-stack{display:flex;gap:2px;height:8px;border-radius:999px;overflow:hidden;background:var(--line)}
.sb-stack span{height:100%;transition:width .5s var(--ease)}
.sb-stack span[style*="width:0%"]{display:none}
.sb-stack .new{background:color-mix(in oklab,var(--accent) 22%,var(--line))}
.sb-stack .learning{background:var(--accent-2)}
.sb-stack .known{background:var(--accent)}
.sb-stack.sm{height:5px}
.sb-legend{display:flex;gap:20px;flex-wrap:wrap;margin-top:10px;font-size:13px;color:var(--muted)}
.sb-legend span{display:inline-flex;align-items:center;gap:6px}
.sb-legend b{color:var(--ink);font-weight:600}
.sb-legend i{width:8px;height:8px;border-radius:50%}
.sb-legend i.new{background:color-mix(in oklab,var(--accent) 22%,var(--line))}
.sb-legend i.learning{background:var(--accent-2)}
.sb-legend i.known{background:var(--accent)}

.sb-card-stage{perspective:1800px;max-width:680px;margin:0 auto}
.sb-flip{display:block;border-radius:var(--r-lg);cursor:pointer;-webkit-tap-highlight-color:transparent}
.sb-flip:focus-visible{outline:2px solid var(--accent-line);outline-offset:4px;border-radius:var(--r-lg)}
.sb-flip-inner{display:grid;transform-style:preserve-3d;transition:transform .6s var(--ease)}
.sb-flip.is-flipped .sb-flip-inner{transform:rotateY(180deg)}
.sb-face{grid-area:1/1;display:flex;flex-direction:column;min-height:300px;padding:20px 24px;border-radius:var(--r-lg);border:1px solid var(--line);background:var(--surface);box-shadow:0 1px 2px rgba(0,0,0,.04),0 18px 44px -22px rgba(0,0,0,.22);-webkit-backface-visibility:hidden;backface-visibility:hidden}
.sb-back{transform:rotateY(180deg);background:color-mix(in oklab,var(--accent) 5%,var(--surface));border-color:var(--accent-line)}
.sb-face-top{display:flex;align-items:center;justify-content:space-between;gap:8px}
.sb-face-label{font-size:13px;font-weight:600;color:var(--muted)}
.sb-back .sb-face-label{color:var(--accent-ink)}
.sb-chip-stage{font-size:12px;font-weight:600;padding:3px 9px;border-radius:999px;background:var(--surface-2);color:var(--muted)}
.sb-chip-stage[data-stage="learning"]{background:color-mix(in oklab,var(--accent-2) 18%,transparent);color:var(--accent-ink)}
.sb-chip-stage[data-stage="known"]{background:var(--accent-soft);color:var(--accent-ink)}
.sb-face-body{flex:1;display:grid;place-items:center;text-align:center;padding:20px 8px;font-size:25px;line-height:1.35;font-weight:600;letter-spacing:-.022em;text-wrap:balance}
.sb-back .sb-face-body{font-size:22px;font-weight:500;color:var(--ink)}
.sb-face-foot{display:flex;align-items:center;justify-content:center;gap:6px;font-size:13px;color:var(--muted)}
.sb-face-foot svg{width:14px;height:14px}
@media (prefers-reduced-motion:reduce){
  .sb-flip-inner,.sb-flip.is-flipped .sb-flip-inner{transform:none;transition:none}
  .sb-back{transform:none;visibility:hidden}
  .sb-flip.is-flipped .sb-back{visibility:visible}
  .sb-flip.is-flipped .sb-front{visibility:hidden}
}
@media (prefers-reduced-motion:no-preference){
  .sb-flip.in-right{animation:sb-in-r .32s var(--ease)}
  .sb-flip.in-left{animation:sb-in-l .32s var(--ease)}
}
@keyframes sb-in-r{from{opacity:0;transform:translateX(28px)}to{opacity:1;transform:none}}
@keyframes sb-in-l{from{opacity:0;transform:translateX(-28px)}to{opacity:1;transform:none}}
.sb-card-controls{display:flex;justify-content:center;margin:20px auto 0;max-width:680px;min-height:72px;align-items:center}
.sb-show{min-width:240px}
.sb-rate{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;width:100%}
.sb-rate-btn{position:relative;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:2px;min-height:72px;padding:10px 6px;border-radius:var(--r-md);border:1px solid var(--line-strong);background:var(--surface);color:var(--ink);cursor:pointer;transition:border-color .15s,background .15s,transform .1s}
.sb-rate-btn:active{transform:scale(.97)}
.sb-rate-btn b{font-size:16px;font-weight:600}
.sb-rate-btn span{font-size:13px;color:var(--muted)}
.sb-rate-btn kbd{position:absolute;top:8px;left:8px;min-width:18px;height:18px;font-size:11px;padding:0 4px;color:var(--muted)}
.sb-rate-btn[data-k="again"] b{color:var(--bad)}
.sb-rate-btn[data-k="hard"] b{color:var(--warn)}
.sb-rate-btn[data-k="good"] b{color:var(--good)}
.sb-rate-btn[data-k="easy"] b{color:var(--accent-ink)}
.sb-rate-btn[data-k="again"]:hover{border-color:var(--bad);background:color-mix(in oklab,var(--bad) 6%,var(--surface))}
.sb-rate-btn[data-k="hard"]:hover{border-color:var(--warn);background:color-mix(in oklab,var(--warn) 7%,var(--surface))}
.sb-rate-btn[data-k="good"]:hover{border-color:var(--good);background:color-mix(in oklab,var(--good) 7%,var(--surface))}
.sb-rate-btn[data-k="easy"]:hover{border-color:var(--accent);background:var(--accent-soft)}
.sb-card-nav{display:flex;align-items:center;justify-content:center;gap:12px;margin-top:14px}
.sb-nav-btn{width:44px;height:44px}
.sb-nav-btn[disabled]{opacity:.35;cursor:default;background:transparent}
.sb-rated{margin:10px 0 0;text-align:center;min-height:20px;font-size:14px;font-weight:600;color:var(--accent-ink)}
.sb-card-area-hint{margin-top:6px}
#cardArea .sb-kbd-hint{margin-top:10px}
.sb-done{text-align:center;padding:40px 16px 24px}
.sb-done-icon{width:60px;height:60px;border-radius:50%;margin:0 auto 16px;display:grid;place-items:center;background:color-mix(in oklab,var(--good) 14%,transparent);color:var(--good)}
.sb-done-icon svg{width:28px;height:28px}
.sb-done h3{margin:0;font-size:24px;letter-spacing:-.025em}
.sb-done p{margin:8px auto 0;color:var(--muted);max-width:44ch}
.sb-done-actions{display:flex;justify-content:center;gap:10px;flex-wrap:wrap;margin-top:22px}

/* ---------- progress, error, empty ---------- */
.sb-progress{max-width:440px;margin:24px auto;text-align:center;padding:24px 0}
.sb-spinner{width:56px;height:56px;margin:0 auto}
.sb-spinner svg{width:56px;height:56px;animation:sb-spin 1.4s linear infinite}
.sb-spinner circle{fill:none;stroke:var(--accent);stroke-width:4;stroke-linecap:round;stroke-dasharray:80 46}
@keyframes sb-spin{to{transform:rotate(360deg)}}
@media (prefers-reduced-motion:reduce){.sb-spinner svg{animation-duration:3s!important;animation-iteration-count:infinite!important}}
.sb-progress h3{margin:20px 0 4px;font-size:24px;font-weight:700;letter-spacing:-.03em}
.sb-progress p{margin:0}
.sb-meter{height:6px;border-radius:999px;background:var(--line);overflow:hidden;margin:22px 0 18px}
.sb-meter span{display:block;height:100%;width:0;border-radius:999px;background:var(--accent);transition:width .4s var(--ease)}
.sb-stage-list{list-style:none;margin:0 auto 24px;padding:0;text-align:left;max-width:300px}
.sb-stage-list li{display:flex;align-items:center;gap:12px;padding:7px 0;font-size:15px;color:var(--faint)}
.sb-stage-list li[data-state="now"]{color:var(--ink);font-weight:600}
.sb-stage-list li[data-state="done"]{color:var(--ink-2)}
.sb-st{width:20px;height:20px;border-radius:50%;border:2px solid var(--line-strong);flex:none;position:relative}
li[data-state="now"] .sb-st{border-color:var(--accent-soft);border-top-color:var(--accent);animation:sb-spin .9s linear infinite}
li[data-state="done"] .sb-st{border-color:var(--good);background:var(--good)}
li[data-state="done"] .sb-st::after{content:"";position:absolute;left:5px;top:2px;width:5px;height:9px;border:solid #fff;border-width:0 2px 2px 0;transform:rotate(45deg)}
.sb-error{text-align:center;max-width:480px;margin:32px auto;padding:24px 0}
.sb-error-icon{width:56px;height:56px;margin:0 auto 16px;border-radius:50%;display:grid;place-items:center;background:color-mix(in oklab,var(--bad) 12%,transparent);color:var(--bad)}
.sb-error-icon svg{width:28px;height:28px}
.sb-error h3{margin:0;font-size:22px;letter-spacing:-.025em}
.sb-error p{margin:8px 0 0;color:var(--muted)}
.sb-error-actions{display:flex;gap:10px;justify-content:center;flex-wrap:wrap;margin-top:22px}
.sb-empty-study{text-align:center;padding:72px 16px;max-width:440px;margin:0 auto}
.sb-empty-study h3{margin:28px 0 6px;font-size:22px;letter-spacing:-.025em}
.sb-empty-study p{margin:0 0 20px;color:var(--muted)}
.sb-empty-art{position:relative;width:132px;height:96px;margin:0 auto}
.sb-ea{position:absolute;inset:0;border-radius:16px;border:1px solid var(--line);background:var(--surface);box-shadow:var(--shadow)}
.sb-ea.c1{transform:rotate(-9deg) translate(-14px,6px);background:var(--surface-2)}
.sb-ea.c2{transform:rotate(6deg) translate(14px,2px);background:var(--surface-2)}
.sb-ea.c3{background:linear-gradient(var(--accent-soft),var(--accent-soft)),var(--surface);border-color:var(--accent-line)}
.sb-ea.c3::before,.sb-ea.c3::after{content:"";position:absolute;left:18px;right:30px;height:7px;border-radius:4px;background:var(--accent);opacity:.5;top:30px}
.sb-ea.c3::after{top:48px;right:52px;opacity:.3}

/* ---------- library ---------- */
.sb-library{padding:28px 36px 36px;border-top:1px solid var(--line);background:color-mix(in oklab,var(--surface-2) 45%,var(--surface))}
.sb-lib-head{display:flex;align-items:baseline;gap:12px;margin-bottom:16px;flex-wrap:wrap}
.sb-lib-head h2{margin:0;font-size:21px;font-weight:700;letter-spacing:-.025em}
.sb-lib-grid{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:16px}
.sb-lib-item{display:flex;flex-direction:column;background:var(--surface);border:1px solid var(--line);border-radius:var(--r-lg);overflow:hidden;transition:border-color .2s,box-shadow .2s}
.sb-lib-item:hover{border-color:var(--line-strong)}
.sb-lib-item[data-active]{border-color:var(--accent-line);box-shadow:0 0 0 3px var(--accent-soft)}
.sb-lib-open{display:flex;flex-direction:column;gap:8px;width:100%;padding:16px 18px 14px;border:0;background:transparent;color:inherit;text-align:left;cursor:pointer;font:inherit}
.sb-lib-open:focus-visible{outline-offset:-3px;border-radius:var(--r-lg) var(--r-lg) 0 0}
.sb-lib-top{display:flex;align-items:center;gap:8px;min-height:24px}
.sb-lib-date{font-size:13px;color:var(--muted)}
.sb-lib-open-tag{margin-left:auto;font-size:12px;font-weight:600;color:var(--accent-ink)}
.sb-lib-title{font-size:17px;font-weight:600;letter-spacing:-.018em;line-height:1.3;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden;min-height:2.6em}
.sb-lib-stats{display:flex;gap:14px;flex-wrap:wrap;font-size:13px;color:var(--muted)}
.sb-lib-stats b{color:var(--ink);font-weight:600}
.sb-lib-stats .is-due b{color:var(--accent-ink)}
.sb-lib-actions{display:flex;align-items:center;gap:2px;padding:6px 8px;border-top:1px solid var(--line)}
.sb-lib-actions .zl-btn{padding:0 10px;color:var(--ink-2)}
.sb-lib-actions .zl-btn:hover{color:var(--ink);background:var(--surface-2)}
.sb-lib-actions .sb-del{color:var(--bad)}
.sb-lib-actions .sb-del:hover{color:var(--bad);background:color-mix(in oklab,var(--bad) 8%,transparent)}

/* ---------- menu + dialogs ---------- */
.sb-menu{position:absolute;z-index:70;width:270px;padding:6px;background:var(--raised);border:1px solid var(--line);border-radius:var(--r-md);box-shadow:var(--shadow-lg)}
.sb-menu button{display:flex;flex-direction:column;align-items:flex-start;gap:2px;width:100%;padding:10px 12px;border:0;border-radius:10px;background:transparent;color:var(--ink);text-align:left;cursor:pointer;font:inherit}
.sb-menu button:hover,.sb-menu button:focus-visible{background:var(--surface-2);outline:none}
.sb-menu b{font-size:15px;font-weight:600}
.sb-menu span{font-size:13px;color:var(--muted)}
@media (prefers-reduced-motion:no-preference){.sb-menu:not([hidden]){animation:sb-fade .16s var(--ease)}}
.sb-mode-card{display:flex;gap:12px;align-items:flex-start;padding:14px 16px;border-radius:var(--r-md);background:var(--surface-2)}
.sb-mode-card .sb-mode-dot{width:10px;height:10px;margin-top:6px}
.sb-mode-card b{font-size:15px}
.sb-mode-card p{margin:2px 0 0;font-size:14px;color:var(--muted);line-height:1.45}
.sb-key-row{display:flex;gap:8px}
.sb-key-row .zl-input{flex:1;min-width:0;font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:16px}
.sb-dialog-foot{justify-content:flex-start}

/* ---------- bento visuals ---------- */
.sb-viz-srs svg{width:100%;height:auto;overflow:visible}
.sb-viz-srs .ax{stroke:var(--line-strong);stroke-width:2;stroke-linecap:round}
.sb-viz-srs .arc{fill:none;stroke:var(--accent);stroke-width:2.5;stroke-linecap:round;opacity:.45}
.sb-viz-srs .arc.strong{opacity:1}
.sb-viz-srs .dot{fill:var(--surface);stroke:var(--accent);stroke-width:2.5}
.sb-viz-srs .dot.end{fill:var(--accent)}
.sb-viz-srs text{fill:var(--muted);font:500 12px var(--font)}
.sb-viz-rates{display:flex;gap:8px;margin-top:14px;flex-wrap:wrap}
.sb-viz-rates span{padding:6px 14px;border-radius:999px;border:1px solid var(--line);font-size:13px;font-weight:600;color:var(--ink-2)}
.sb-viz-rates span.on{background:var(--accent);border-color:var(--accent);color:var(--on-accent)}
.sb-viz-tex{font-size:30px;color:var(--ink);padding:18px 0 4px}
.sb-viz-tex .katex-display{margin:0;text-align:left}
.sb-viz-tex .katex-display > .katex{text-align:left}
.sb-viz-pdf{display:flex;align-items:flex-end;gap:16px;flex-wrap:wrap}
.sb-viz-pdf .pg{width:84px;height:106px;border-radius:10px;border:1px solid var(--line);background:var(--surface-2);padding:14px 12px;display:flex;flex-direction:column;gap:7px;box-shadow:6px 6px 0 -1px var(--surface),6px 6px 0 0 var(--line)}
.sb-viz-pdf .pg i{display:block;height:5px;border-radius:3px;background:var(--line-strong)}
.sb-viz-pdf .pg i.s{width:60%}
.sb-viz-quiz{display:flex;align-items:center;gap:28px}
.sb-viz-quiz .opts{display:flex;flex-direction:column;gap:8px;flex:1;max-width:340px}
.sb-viz-quiz .opt{display:flex;align-items:center;gap:10px;height:44px;padding:0 12px;border-radius:12px;border:1px solid var(--line);font-size:15px;font-weight:500}
.sb-viz-quiz .opt b{width:24px;height:24px;border-radius:7px;display:grid;place-items:center;background:var(--surface-2);font-size:12px;color:var(--muted)}
.sb-viz-quiz .opt svg{width:16px;height:16px;margin-left:auto}
.sb-viz-quiz .opt.good{border-color:var(--good);background:color-mix(in oklab,var(--good) 9%,transparent)}
.sb-viz-quiz .opt.good b{background:var(--good);color:#fff}
.sb-viz-quiz .opt.good svg{color:var(--good)}
.sb-viz-quiz .opt.bad{border-color:var(--bad);background:color-mix(in oklab,var(--bad) 7%,transparent)}
.sb-viz-quiz .opt.bad b{background:var(--bad);color:#fff}
.sb-viz-quiz .opt.bad svg{color:var(--bad)}
.sb-viz-quiz .ring{width:96px;height:96px;flex:none}
.sb-viz-quiz .ring circle{fill:none;stroke-width:8}
.sb-viz-quiz .ring .trk{stroke:var(--line)}
.sb-viz-quiz .ring .val{stroke:var(--good);stroke-linecap:round;transform:rotate(-90deg);transform-origin:40px 40px}
.sb-viz-quiz .ring text{fill:var(--ink);font:700 17px var(--font)}
.sb-viz-anki code{display:block;margin-top:6px;padding:9px 12px;border-radius:9px;background:var(--surface-2);font:13px/1.4 ui-monospace,SFMono-Regular,Menlo,monospace;color:var(--ink-2);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.sb-viz-anki code:first-child{color:var(--muted)}
.sb-viz-anki i{font-style:normal;color:var(--accent-ink);margin:0 8px}
.sb-viz-search .fld{display:flex;align-items:center;gap:8px;height:42px;padding:0 14px;border-radius:999px;border:1px solid var(--accent);box-shadow:0 0 0 4px var(--accent-soft);font-size:15px;color:var(--ink)}
.sb-viz-search .fld svg{width:16px;height:16px;color:var(--muted)}
.sb-viz-search .caret{width:1.5px;height:18px;background:var(--accent);margin-left:-6px}
@media (prefers-reduced-motion:no-preference){.sb-viz-search .caret{animation:sb-pulse 1s steps(2) infinite}}
.sb-viz-search .row{padding:10px 4px;border-bottom:1px solid var(--line)}
.sb-viz-search .row:last-child{border-bottom:0}
.sb-viz-search .row b{display:block;font-size:15px}
.sb-viz-search .row span{font-size:13px;color:var(--muted)}

/* ---------- responsive ---------- */
@media (max-width:980px){
  .sb-work{grid-template-columns:1fr}
  .sb-compose{border-right:0;border-bottom:1px solid var(--line)}
  .sb-notes{min-height:220px}
  .sb-study{min-height:0}
}
@media (max-width:720px){
  .sb-app .zl-appbar{padding:12px 16px}
  .sb-app .zl-appbar-title{flex-basis:100%}
  .sb-app .zl-btn-sm{min-height:44px}
  .sb-mode{min-height:44px}
  .sb-compose,.sb-study,.sb-library{padding:20px 16px}
  .sb-set-head{flex-direction:column;gap:12px}
  .sb-set-head h2{font-size:26px}
  .sb-tabs button{padding:0 6px;flex:1 1 0;min-width:0;gap:4px}
  .sb-tl-long{display:none}
  .sb-tl-short{display:inline}
  .sb-tab-n:not([data-due="1"]){display:none}
  .sb-sec,.sb-term{grid-template-columns:1fr;gap:8px}
  .sb-overview{font-size:17px}
  .sb-q{font-size:21px}
  .sb-opt{font-size:16px;gap:12px;padding:10px 12px}
  .sb-result{flex-direction:column;text-align:center;gap:24px}
  .sb-result-actions{justify-content:center}
  .sb-face{min-height:260px;padding:16px 18px}
  .sb-face-body{font-size:21px}
  .sb-back .sb-face-body{font-size:19px}
  .sb-rate{gap:8px}
  .sb-rate-btn{min-height:64px}
  .sb-rate-btn kbd{display:none}
  #cardArea .sb-kbd-hint{display:none}
  .sb-lib-grid{grid-template-columns:1fr}
  .sb-viz-quiz{gap:16px}
  .sb-viz-quiz .ring{width:76px;height:76px}
  .sb-search{max-width:none;flex-basis:100%}
}
@media (hover:none){.sb-kbd-hint.sb-center{display:none}}