/* A stable shared frame. Only its active tab can scroll or receive input. */
.notebook-focus-dialog.study-hub{--study-footer-bottom:20px;inset:auto;margin:0;transform:translate(-50%,-50%);width:min(440px,calc(100vw - 24px));height:min(600px,calc(100dvh - 24px));max-width:none;max-height:none}
.study-hub-tabs{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));flex:none;gap:4px;margin:4px 20px 12px;padding:4px;border:1px solid var(--line);border-radius:9px;background:var(--soft)}
.study-hub-tabs button{min-width:0;min-height:38px;padding:6px 2px;border:0;border-radius:6px;color:var(--muted);font-size:.9375rem;line-height:1.4;white-space:nowrap}
.study-hub-tabs button[aria-selected='true']{background:var(--panel);color:var(--accent-ink);box-shadow:0 1px 3px #0000000b}
.study-hub-panel{display:flex;flex-direction:column;flex:1;min-height:0;min-width:0;overflow:hidden}
.study-hub [hidden]{display:none!important}
.study-hub .notebook-flash-stage{flex:1;width:auto;height:auto;aspect-ratio:auto;margin-top:0}
.study-hub .notebook-relay-bar{position:static;flex:none;height:auto;padding-bottom:var(--study-footer-bottom)}
.study-hub-tracing.tracing-dialog{position:relative;inset:auto;transform:none;display:flex;flex-direction:column;flex:1;align-items:center;min-height:0;width:100%;height:100%;max-width:none;max-height:none;margin:0;padding:0 20px var(--study-footer-bottom);border:0;border-radius:0;box-shadow:none;overflow:auto}
/* Equal zero-basis flex zones keep the writing square centered across every card. */
.tracing-quiz-sheet{display:flex;flex-direction:column;align-items:center;flex:none;width:100%;height:var(--tracing-sheet-height,390px);min-width:0;padding:0 12px;border:1px solid var(--line);border-radius:9px;background:var(--tracing-paper);box-sizing:border-box}
.study-hub-tracing .tracing-header{display:none;margin:0}
.study-hub-tracing .tracing-heading h2{display:none}
.study-hub-tracing .tracing-stage{flex:0 0 auto;width:var(--tracing-size);height:var(--tracing-size);max-width:100%;margin:0 auto;border-radius:0;box-shadow:none;transform:none}
/* A faint, non-interactive田 guide stays beneath every glyph and ink layer. */
.study-hub-tracing .tracing-stage{--tracing-grid-ink:#E7E6DF}
[data-theme="dark"] .study-hub-tracing .tracing-stage{--tracing-grid-ink:#475347}
.study-hub-tracing .tracing-stage::before{content:"";position:absolute;inset:1px;z-index:0;box-sizing:border-box;border:0;border-radius:0;background-image:repeating-linear-gradient(to right,var(--tracing-grid-ink) 0 4px,transparent 4px 8px),repeating-linear-gradient(to right,var(--tracing-grid-ink) 0 4px,transparent 4px 8px),repeating-linear-gradient(to right,var(--tracing-grid-ink) 0 4px,transparent 4px 8px),repeating-linear-gradient(to bottom,var(--tracing-grid-ink) 0 4px,transparent 4px 8px),repeating-linear-gradient(to bottom,var(--tracing-grid-ink) 0 4px,transparent 4px 8px),repeating-linear-gradient(to bottom,var(--tracing-grid-ink) 0 4px,transparent 4px 8px);background-size:100% 1px,100% 1px,100% 1px,1px 100%,1px 100%,1px 100%;background-position:top,bottom,center,left,right,center;background-repeat:no-repeat;pointer-events:none}
.study-hub-tracing .tracing-guide{z-index:1}
.study-hub-tracing .tracing-canvas{z-index:2}
.study-hub-tracing .tracing-quiz-notice{z-index:3}
.study-hub-tracing .tracing-actions{flex:none;align-self:stretch;grid-template-columns:repeat(5,minmax(0,1fr));margin-top:12px;gap:8px}
.study-hub-tracing .tracing-actions button{height:50px}
.tracing-quiz-question{flex:1 1 0;min-height:0;align-self:stretch;display:flex;align-items:center;justify-content:center;margin:0;min-width:0;font-size:16px;line-height:1.5;color:var(--ink);text-align:center;overflow:hidden;touch-action:pan-y}
.tracing-quiz-question p,.tracing-quiz-answer p{width:100%;margin:0;line-height:1.5;overflow-wrap:anywhere;white-space:normal}
.tracing-quiz-question p{word-break:keep-all;overflow-wrap:break-word;text-wrap:balance}
.tracing-quiz-question .tracing-quiz-word{white-space:nowrap}
.tracing-quiz-question img{display:inline-block;height:1em;width:auto;max-width:100%;vertical-align:-2px;object-fit:contain;mix-blend-mode:multiply}
/* Lower inline strokes without changing line spacing or saved per-image offsets. */
:root .study-hub .tracing-quiz-question img{position:relative;top:calc(var(--content-glyph-offset,0px) + 2px)}
/* Both zones have zero basis and zero minimum: text cannot bias their actual heights. */
.tracing-quiz-answer-space{position:relative;flex:1 1 0;align-self:stretch;display:flex;align-items:center;justify-content:center;min-width:0;min-height:0;text-align:center}
.tracing-quiz-answer{display:flex;align-items:center;justify-content:center;width:100%;min-width:0;height:100%;margin:0;font-size:20px;line-height:1.5;color:var(--accent-ink);text-align:center;touch-action:pan-y;visibility:hidden;opacity:0;user-select:none}
.tracing-quiz-notice{position:absolute;inset:0;z-index:2;display:flex;align-items:center;justify-content:center;margin:0;padding:18px;background:var(--tracing-paper);color:#888888;font-size:14px;line-height:1.5;text-align:center;pointer-events:none}
.tracing-quiz-answer[data-revealed='true']{visibility:visible;opacity:1;user-select:text;transition:opacity .25s ease}
@media(prefers-reduced-motion:reduce){.tracing-quiz-answer[data-revealed='true']{transition:none}}
.study-hub-memo.review-memo-dialog{position:relative;inset:auto;transform:none;display:flex;flex:1;min-height:0;width:100%;height:100%;max-height:none;margin:0;border:0;border-radius:0;box-shadow:none;overflow:hidden}
.study-hub-memo .review-memo-header{padding-top:0;padding-bottom:12px}
.study-hub-memo .review-memo-editor{padding-top:12px}
.study-hub-memo .review-memo-footer{padding-bottom:var(--study-footer-bottom)}
.study-hub-memo .review-memo-character{font-size:2rem}
.study-hub-memo .review-memo-reading{font-size:1.125rem}
.study-hub-confirm{position:fixed;inset:0;margin:auto;max-width:calc(100vw - 32px);width:370px;padding:22px;border:1px solid var(--line);border-radius:14px;background:var(--panel);color:var(--ink);box-shadow:0 16px 60px #0003}
.study-hub-confirm::backdrop{background:#0006}
.study-hub-confirm h2{margin:0 0 12px;font-size:1.1rem;font-weight:500}
.study-hub-confirm p{margin:0 0 20px;font-size:.9375rem;line-height:1.6}
.study-hub-confirm-actions{display:flex;justify-content:flex-end;gap:8px}
.study-hub-confirm-actions button{min-height:44px;padding:8px 12px;border:1px solid var(--line);border-radius:7px;background:var(--surface);color:var(--accent-ink);white-space:nowrap}
.study-hub-confirm-actions [data-study-leave='save']{background:var(--brand);color:#fff}
.study-hub-confirm-error{color:var(--review-red)}
@media(max-width:1023px){
  .notebook-focus-dialog.study-hub{--study-footer-bottom:max(16px,env(safe-area-inset-bottom,0px))}
  .study-hub-tabs{margin-inline:14px}
  .study-hub-tracing.tracing-dialog{padding-inline:14px}
  .tracing-quiz-sheet{padding-inline:8px}
}
@media(hover:hover) and (pointer:fine){.study-hub-tabs button:not(:disabled):hover{color:var(--accent-ink)}}
.study-hub[data-compact='true'] .notebook-focus-heading{padding-top:6px}
.study-hub[data-compact='true'] .study-hub-tabs{margin-bottom:8px}
.study-hub[data-compact='true'] .review-memo-header{padding-bottom:8px}
.study-hub[data-compact='true'] .review-memo-editor{padding-top:10px}

/* Fixed inner text slot; equal outer zones and the writing square never resize per card. */
.tracing-quiz-question-slot{flex:none;width:100%;height:54px;min-height:54px;display:flex;align-items:center;justify-content:center;text-align:center}
.tracing-quiz-question-line{display:block;white-space:nowrap}