:root {
  --bg: #f5f6f8;
  --panel: #ffffff;
  --text: #111827;
  --muted: #6b7280;
  --border: #e5e7eb;
  --accent: #111827;
  --accent-soft: #eef2ff;
  --review: #fff7ed;
  --known: #ecfdf5;
  --danger: #991b1b;
  --radius: 22px;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}
button { font: inherit; }
.shell { max-width: 1120px; margin: 0 auto; padding: 28px 18px 48px; }
.topbar { display: flex; gap: 20px; justify-content: space-between; align-items: flex-start; margin-bottom: 18px; }
.topbar h1 { margin: 4px 0 8px; font-size: clamp(1.8rem, 5vw, 3.3rem); line-height: .98; max-width: 760px; }
.sub { color: var(--muted); margin: 0; font-size: 1.05rem; }
.eyebrow { font-size: .74rem; letter-spacing: .14em; font-weight: 800; color: var(--muted); margin: 0; }
.streak { min-width: 108px; padding: 15px 18px; border: 1px solid var(--border); border-radius: 18px; background: var(--panel); text-align: center; }
.streak span { display: block; font-size: 1.8rem; font-weight: 900; }
.streak small { color: var(--muted); }
.panel { background: var(--panel); border: 1px solid var(--border); border-radius: var(--radius); }
.setup { display: flex; justify-content: space-between; gap: 16px; align-items: center; padding: 16px 18px; margin-bottom: 12px; }
.setup h2, .setup p { margin: 0; }
.setup p { margin-top: 3px; color: var(--muted); }
.setup-actions, .confidence-actions, .nav-actions { display: flex; gap: 10px; flex-wrap: wrap; }
button { border: 0; cursor: pointer; min-height: 44px; border-radius: 14px; padding: 10px 15px; font-weight: 800; }
button:focus-visible { outline: 3px solid #93c5fd; outline-offset: 2px; }
.primary { background: var(--accent); color: white; }
.ghost { background: #f9fafb; color: var(--text); border: 1px solid var(--border); }
.full { width: 100%; }
.days { display: grid; grid-template-columns: repeat(7, 1fr); gap: 7px; padding: 8px; margin-bottom: 12px; overflow-x: auto; }
.day-tab { min-width: 106px; background: transparent; color: var(--muted); border: 1px solid transparent; }
.day-tab strong { display: block; color: var(--text); font-size: .86rem; }
.day-tab.active { background: var(--accent); color: white; }
.day-tab.active strong { color: white; }
.dashboard { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; margin-bottom: 12px; }
.metric { padding: 16px; }
.metric span, .metric small { display: block; color: var(--muted); }
.metric strong { display: block; font-size: 1.8rem; margin: 4px 0; }
.study-grid { display: grid; grid-template-columns: 320px minmax(0, 1fr); gap: 12px; align-items: start; }
.mission { padding: 20px; position: sticky; top: 12px; }
.mission h2 { margin: 6px 0; font-size: 1.55rem; }
.mission > p:not(.eyebrow) { color: var(--muted); line-height: 1.5; }
.mission-block { border-top: 1px solid var(--border); padding: 14px 0; }
.mission-block span { font-size: .72rem; letter-spacing: .08em; text-transform: uppercase; color: var(--muted); font-weight: 900; }
.mission-block p { margin: 5px 0 0; line-height: 1.45; }
.card-area { min-width: 0; }
.card-meta { display: flex; justify-content: space-between; align-items: center; gap: 8px; margin: 6px 4px 9px; color: var(--muted); font-size: .9rem; }
.badges { display: flex; flex-wrap: wrap; gap: 6px; justify-content: flex-end; }
.badge { padding: 5px 9px; border-radius: 999px; background: #e0e7ff; color: #3730a3; font-weight: 800; font-size: .75rem; }
.badge.subtle { background: #f3f4f6; color: #4b5563; }
.flashcard { width: 100%; min-height: 430px; padding: 0; background: var(--panel); border: 1px solid var(--border); border-radius: 30px; text-align: left; overflow: hidden; box-shadow: 0 16px 40px rgba(17,24,39,.06); }
.face { min-height: 430px; padding: clamp(24px, 5vw, 48px); display: flex; flex-direction: column; justify-content: center; }
.front { background: linear-gradient(145deg, #ffffff, #f8fafc); }
.back { background: #ffffff; }
.prompt-label { font-size: .72rem; letter-spacing: .13em; font-weight: 900; color: var(--muted); margin-bottom: 14px; }
.face h2 { font-size: clamp(2rem, 6vw, 4.4rem); letter-spacing: -.04em; margin: 0 0 14px; line-height: .95; }
.front p { font-size: 1.15rem; color: var(--muted); max-width: 620px; line-height: 1.55; }
.tap { margin-top: auto; color: var(--muted); font-weight: 800; }
.back h2 { font-size: clamp(1.7rem, 5vw, 3rem); }
.back-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 10px; width: 100%; }
.back-item { background: #f9fafb; border: 1px solid var(--border); border-radius: 16px; padding: 13px 14px; }
.back-item strong { display: block; font-size: .72rem; letter-spacing: .07em; text-transform: uppercase; color: var(--muted); margin-bottom: 5px; }
.back-item p { margin: 0; line-height: 1.4; }
.back-item.danger { background: #fef2f2; }
.back-item.danger strong { color: var(--danger); }
.memory { grid-column: 1 / -1; background: var(--accent-soft); }
.memory p { font-weight: 900; font-size: 1.05rem; }
.hidden { display: none !important; }
.confidence { display: flex; justify-content: space-between; align-items: center; gap: 12px; padding: 13px 0; }
.confidence p { margin: 0; color: var(--muted); }
.review { background: var(--review); color: #9a3412; border: 1px solid #fed7aa; }
.known { background: var(--known); color: #065f46; border: 1px solid #a7f3d0; }
.nav-actions { justify-content: space-between; margin-top: 10px; }
.review-zone { margin-top: 12px; padding: 22px; display: grid; grid-template-columns: 240px 1fr; gap: 24px; }
.review-zone h2 { margin: 5px 0 0; }
.questions { display: grid; gap: 8px; }
.question { border-bottom: 1px solid var(--border); padding: 8px 0 12px; line-height: 1.4; }
.question:last-child { border-bottom: 0; }
footer { color: var(--muted); font-size: .8rem; line-height: 1.5; padding: 24px 4px 0; }
@media (max-width: 820px) {
  .dashboard { grid-template-columns: repeat(2, 1fr); }
  .study-grid { grid-template-columns: 1fr; }
  .mission { position: static; }
  .review-zone { grid-template-columns: 1fr; }
}
@media (max-width: 560px) {
  .shell { padding: 16px 12px 36px; }
  .topbar { align-items: stretch; }
  .streak { min-width: 92px; padding: 12px; }
  .setup { align-items: stretch; flex-direction: column; }
  .setup-actions button { flex: 1 1 auto; }
  .dashboard { gap: 8px; }
  .metric { padding: 13px; }
  .metric strong { font-size: 1.5rem; }
  .face { padding: 24px; min-height: 390px; }
  .flashcard { min-height: 390px; }
  .back-grid { grid-template-columns: 1fr; }
  .memory { grid-column: auto; }
  .confidence { align-items: stretch; flex-direction: column; }
  .confidence-actions button { flex: 1; }
  .nav-actions button { flex: 1; }
}