/* Fast Revision Mode — fullscreen focus overlay.
   Uses site CSS variables so it matches light + dark themes + site fonts. */
.fr-overlay {
  position: fixed; inset: 0; z-index: 9000;
  background: var(--black);
  color: var(--white);
  font-family: var(--sans, 'DM Sans', system-ui, sans-serif);
  font-weight: 300;
  display: none; flex-direction: column;
}
.fr-overlay.open { display: flex; }

.fr-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 0.9rem 1.5rem;
  border-bottom: 1px solid var(--gray-border);
  flex-shrink: 0; gap: 1rem;
}
.fr-brand {
  font-family: var(--sans); font-weight: 700; letter-spacing: 0.08em;
  color: var(--yellow); font-size: 0.9rem;
}
.fr-brand span { color: var(--white); font-weight: 300; }

.fr-mode-toggle { display: flex; border: 1px solid var(--gray-border); }
.fr-mode-toggle button {
  background: transparent; color: var(--gray); border: none; cursor: pointer;
  padding: 0.45rem 0.9rem; font: inherit; font-size: 0.72rem;
  letter-spacing: 0.1em; text-transform: uppercase; font-weight: 500;
  transition: color 0.2s, background 0.2s;
}
.fr-mode-toggle button.active { background: var(--yellow); color: var(--badge-text); font-weight: 600; }
.fr-header-right { display: flex; gap: 0.5rem; align-items: center; flex-wrap: wrap; }

.fr-btn {
  background: transparent; color: var(--white);
  border: 1px solid var(--gray-border);
  padding: 0.45rem 0.9rem; font: inherit; font-size: 0.72rem;
  letter-spacing: 0.1em; text-transform: uppercase; cursor: pointer;
  font-weight: 500;
  transition: color 0.2s, border-color 0.2s, background 0.2s;
}
.fr-btn:hover { color: var(--yellow); border-color: var(--yellow); }
.fr-btn.fr-primary {
  color: var(--badge-text); background: var(--yellow); border-color: var(--yellow);
  font-weight: 600;
}
.fr-btn.fr-primary:hover { background: var(--white); border-color: var(--white); color: var(--black); }
.fr-btn.fr-danger { color: var(--danger); border-color: var(--gray-border); }
.fr-btn.fr-danger:hover { color: var(--danger); border-color: var(--danger); }

.fr-body {
  flex: 1; display: flex; align-items: center; justify-content: center;
  padding: 2rem 1.5rem; overflow-y: auto;
}

/* ─── Topic picker ─── */
.fr-picker {
  width: 100%; max-width: 820px;
  display: flex; flex-direction: column; gap: 1.2rem;
}
.fr-picker h2 {
  font-family: var(--serif); font-weight: 400; font-size: 2rem; margin: 0;
  line-height: 1.15; color: var(--white); text-align: center;
}
.fr-picker-sub {
  color: var(--gray); font-size: 0.88rem; margin-top: -0.4rem;
  text-align: center; font-weight: 300;
}
.fr-search {
  background: var(--card-bg); border: 1px solid var(--gray-border);
  color: var(--white); padding: 0.7rem 0.9rem;
  font: 400 0.9rem var(--sans); outline: none;
}
.fr-search:focus { border-color: var(--yellow); }
/* Resume card at top of picker */
.fr-resume {
  display: flex; align-items: center; gap: 1rem; flex-wrap: wrap;
  background: var(--card-bg);
  border: 1px solid var(--yellow);
  padding: 1rem 1.2rem;
  box-shadow: 0 0 0 1px rgba(245, 197, 24, 0.15) inset;
}
.fr-resume-left { flex: 1; min-width: 220px; }
.fr-resume-label {
  font-size: 0.62rem; letter-spacing: 0.15em; text-transform: uppercase;
  color: var(--yellow); font-weight: 600; margin-bottom: 0.3rem;
}
.fr-resume-title {
  font-family: var(--serif); font-weight: 400; font-size: 1.2rem;
  color: var(--white); line-height: 1.2; margin-bottom: 0.25rem;
}
.fr-resume-meta { font-size: 0.78rem; color: var(--gray); }
.fr-resume-right { display: flex; gap: 0.4rem; align-items: center; }
.fr-resume-discard {
  padding: 0.45rem 0.65rem; font-size: 0.95rem; letter-spacing: 0;
  text-transform: none; font-weight: 400;
}

.fr-topic-list {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 0.5rem; max-height: 60vh; overflow-y: auto; padding-right: 4px;
}
.fr-topic-card {
  background: var(--card-bg); border: 1px solid var(--gray-border);
  padding: 0.85rem 1rem; cursor: pointer; text-align: left;
  color: var(--white); font: inherit;
  transition: border-color 0.2s, background 0.2s;
}
.fr-topic-card:hover { border-color: var(--yellow); background: var(--card-hover); }
.fr-topic-card .ft-subject {
  font-size: 0.58rem; letter-spacing: 0.16em; text-transform: uppercase;
  color: var(--yellow); margin-bottom: 0.3rem; font-weight: 600;
}
.fr-topic-card .ft-name { font-size: 0.95rem; line-height: 1.3; font-weight: 400; }

/* ─── Card stage (centered column) ─── */
.fr-stage {
  width: 100%; max-width: 820px; margin: 0 auto;
  display: flex; flex-direction: column; align-items: stretch; gap: 1rem;
}
.fr-stage-top {
  display: flex; align-items: center; justify-content: space-between;
  gap: 0.8rem; width: 100%;
}
.fr-crumb {
  font-size: 0.68rem; letter-spacing: 0.15em; text-transform: uppercase;
  color: var(--yellow); font-weight: 600;
}
.fr-counter {
  font-size: 0.72rem; color: var(--gray); letter-spacing: 0.06em;
  font-variant-numeric: tabular-nums;
}
.fr-progress-track {
  width: 100%; height: 2px; background: var(--gray-border); overflow: hidden;
}
.fr-progress-fill {
  height: 100%; background: var(--yellow); width: 0%;
  transition: width 0.25s linear;
}

/* The flashcard */
.fr-card {
  width: 100%; min-height: 360px;
  background: var(--card-bg); border: 1px solid var(--gray-border);
  padding: 2.2rem 2rem;
  display: flex; flex-direction: column; justify-content: center; align-items: center;
  gap: 1rem; text-align: center;
  transition: border-color 0.25s ease;
}
.fr-card.flip { cursor: pointer; }
.fr-card.flip:hover { border-color: var(--yellow); }

.fr-card h3 {
  font-family: var(--serif); font-weight: 400;
  font-size: clamp(1.6rem, 3vw, 2rem);
  margin: 0; line-height: 1.2;
  color: var(--white); text-align: center; letter-spacing: 0;
  max-width: 36ch;
}

/* Back-side body: left-aligned prose in a max-width block, but block itself centered */
.fr-card-desc {
  color: var(--white); font-size: 0.98rem; line-height: 1.7;
  font-weight: 300; font-family: var(--sans);
  max-width: 60ch; text-align: left; width: 100%;
}
.fr-card-desc p { margin-bottom: 0.8rem; }
.fr-card-desc p:last-child { margin-bottom: 0; }
.fr-card-desc strong { color: var(--white); font-weight: 600; }
.fr-card-desc em { font-style: italic; color: var(--yellow); opacity: 0.9; }

/* Markdown elements rendered by `marked` inside the writeup body — tables,
   lists, blockquotes, code spans / blocks, sub-headings. Without these the
   FR card showed raw Markdown when launched from pages that don't load
   marked themselves (dashboard, tests, videos). */
.fr-card-desc h3 { font-family: var(--serif); font-size: 1.05rem; color: var(--yellow); margin: 0.9rem 0 0.4rem; font-weight: 400; }
.fr-card-desc h4 { font-family: var(--serif); font-size: 0.98rem; color: var(--white); margin: 0.7rem 0 0.3rem; font-weight: 500; }
.fr-card-desc ul, .fr-card-desc ol { margin: 0.4rem 0 0.8rem 1.4rem; padding-left: 0.2rem; }
.fr-card-desc li { margin-bottom: 0.25rem; }
.fr-card-desc blockquote {
  border-left: 3px solid var(--yellow);
  padding: 0.1rem 0 0.1rem 0.9rem;
  margin: 0.7rem 0;
  color: var(--gray); font-style: italic;
}
.fr-card-desc blockquote strong { color: var(--yellow); font-style: normal; }
.fr-card-desc code {
  background: rgba(245,197,24,0.08); color: var(--yellow);
  padding: 0.05rem 0.35rem; font-size: 0.88em;
  font-family: 'SF Mono', ui-monospace, Menlo, Consolas, monospace;
}
.fr-card-desc pre {
  background: rgba(0,0,0,0.4); border: 1px solid var(--gray-border);
  padding: 0.7rem; overflow-x: auto; margin: 0.6rem 0;
}
.fr-card-desc pre code { background: none; color: var(--white); padding: 0; }
.fr-card-desc table {
  width: 100%; border-collapse: collapse; margin: 0.7rem 0;
  font-size: 0.88rem;
}
.fr-card-desc th, .fr-card-desc td {
  border: 1px solid var(--gray-border);
  padding: 0.4rem 0.6rem;
  text-align: left;
}
.fr-card-desc th { background: rgba(245,197,24,0.06); color: var(--yellow); font-weight: 600; }

/* Inline equation styling — monospace, spaced, visually distinct */
.fr-card-desc .fr-eq {
  font-family: 'SF Mono', ui-monospace, Menlo, Consolas, monospace;
  background: rgba(245, 197, 24, 0.08);
  color: var(--yellow);
  padding: 0.1rem 0.45rem;
  border: 1px solid rgba(245, 197, 24, 0.18);
  font-size: 0.92em;
  white-space: nowrap;
  letter-spacing: 0.02em;
}
.fr-card-desc .katex, .fr-card-desc .katex-display { color: var(--white); }
.fr-card-desc .katex-display {
  overflow-x: auto; max-width: 100%; padding: 0.35rem 0;
  margin: 0.6rem 0; text-align: center;
}

.fr-card-kw { display: flex; flex-wrap: wrap; gap: 0.35rem; justify-content: center; margin-top: 0.4rem; }
.fr-card-kw span {
  font-size: 0.65rem; color: var(--yellow);
  padding: 0.18rem 0.55rem;
  border: 1px solid var(--gray-border);
  font-family: var(--sans); font-weight: 500;
  letter-spacing: 0.04em; text-transform: lowercase;
}

.fr-flip-hint {
  font-size: 0.68rem; color: var(--gray);
  letter-spacing: 0.14em; text-transform: uppercase;
  font-weight: 500;
  margin-top: 0.5rem;
}

.fr-controls {
  display: flex; gap: 0.5rem; flex-wrap: wrap;
  justify-content: space-between; width: 100%;
  padding-top: 0.5rem;
}
.fr-controls .fr-left, .fr-controls .fr-right { display: flex; gap: 0.5rem; flex-wrap: wrap; }

.fr-empty {
  color: var(--gray); text-align: center; padding: 3rem 1rem;
  font-size: 0.9rem; font-family: var(--sans);
}

@media (max-width: 600px) {
  .fr-header { padding: 0.7rem 1rem; flex-wrap: wrap; }
  .fr-body { padding: 1rem; }
  .fr-card { padding: 1.4rem 1.2rem; min-height: 300px; }
  .fr-card-desc { font-size: 0.92rem; }
}

/* ─── Completion share card ─── */
.fr-share-overlay {
  position: fixed; inset: 0; z-index: 10002;
  background: rgba(0,0,0,0.85); backdrop-filter: blur(6px);
  display: flex; align-items: center; justify-content: center;
  padding: 1rem; overflow-y: auto;
}
.fr-share-card {
  background: #0a0a0a; border: 1px solid var(--gray-border, #252525);
  max-width: 440px; width: 100%; padding: 1.4rem;
  text-align: center; color: #f8f7f4;
}
.fr-share-card h2 { font-family: var(--serif, Georgia); font-weight: 400; font-size: 1.6rem; margin-bottom: 0.4rem; color: var(--yellow, #f5c518); }
.fr-share-card p { font-size: 0.9rem; color: #bbb; margin-bottom: 1rem; }
.fr-share-card strong { color: #f8f7f4; }
.fr-share-preview {
  display: block; margin: 0 auto 1rem;
  max-width: 240px; border: 1px solid var(--gray-border, #252525);
  border-radius: 4px;
  box-shadow: 0 8px 32px rgba(245,197,24,0.15);
}
.fr-share-actions { display: flex; flex-direction: column; gap: 0.5rem; margin: 0.5rem 0 0.8rem; }
.fr-share-actions .fr-btn {
  padding: 0.7rem 1rem; font-size: 0.85rem; font-family: var(--sans, system-ui);
  background: transparent; border: 1px solid var(--gray-border, #252525);
  color: #f8f7f4; cursor: pointer; transition: all 0.15s;
}
.fr-share-actions .fr-btn:hover { border-color: var(--yellow, #f5c518); color: var(--yellow, #f5c518); }
.fr-share-actions .fr-share-continue { background: var(--yellow, #f5c518); color: #0a0a0a; font-weight: 600; border-color: transparent; }
.fr-share-actions .fr-share-continue:hover { background: #e0b516; color: #0a0a0a; }
.fr-share-hint { font-size: 0.72rem; color: #666; letter-spacing: 0.08em; text-transform: uppercase; }

/* ─── Revision HUD (streak + syllabus progress, used on dashboard) ─── */
.rev-hud {
  display: flex; gap: 0.8rem; flex-wrap: wrap;
  padding: 1rem; border: 1px solid var(--gray-border, #252525);
  background: #111108; margin: 1rem 0;
}
.rev-hud-stat { flex: 1 1 140px; min-width: 0; padding: 0.2rem 0.6rem; }
.rev-hud-label { font-size: 0.6rem; letter-spacing: 0.15em; text-transform: uppercase; color: #888; }
.rev-hud-value { font-size: 1.8rem; font-weight: 700; color: var(--yellow, #f5c518); line-height: 1.1; margin-top: 0.15rem; }
.rev-hud-sub   { font-size: 0.7rem; color: #888; margin-top: 0.2rem; }
.rev-hud-stat.danger .rev-hud-value { color: #e84545; }
.rev-hud-progress {
  height: 4px; background: #252525; margin-top: 0.4rem; overflow: hidden;
}
.rev-hud-progress-fill { height: 100%; background: var(--yellow, #f5c518); width: 0%; transition: width 0.6s ease; }

/* Report button + Focus button live side-by-side in the stage header.
   Both are in-flow flex children; stage-top already uses space-between so
   crumb/counter sit left and these two sit right with the nav-style gap. */
.fr-stage-top { flex-wrap: wrap; }
.fr-stage-top .fr-counter { margin-right: auto; }  /* push buttons to the right */
.fr-report-btn.report-err-btn {
  padding: 0.3rem 0.6rem; font-size: 0.62rem;
  letter-spacing: 0.08em;
  white-space: nowrap;
}

/* Equation card — visually distinct from concept cards */
.fr-card.is-equation {
  border-color: rgba(245,197,24,0.35);
  background: linear-gradient(180deg, rgba(245,197,24,0.04), transparent 60%);
}
.fr-card.is-equation h3 {
  font-family: var(--sans, system-ui);
  font-size: 0.72rem; letter-spacing: 0.15em;
  text-transform: uppercase; color: var(--yellow, #f5c518);
  font-weight: 700; margin-bottom: 0.8rem;
}

/* Concept animation box on the flashcard back */
.fr-anim-box {
  margin: 0.2rem 0 0.9rem;
  padding: 0.5rem;
  background: rgba(245,197,24,0.03);
  border: 1px solid rgba(245,197,24,0.12);
  border-radius: 2px;
}
.fr-anim-cap {
  font-size: 0.66rem; color: var(--gray, #888);
  text-align: center; letter-spacing: 0.04em;
  font-style: italic; margin-top: 0.2rem;
}

/* Focus mode button on the Fast Revision stage top */
.fr-focus-btn {
  padding: 0.35rem 0.75rem;
  font-size: 0.7rem; letter-spacing: 0.08em; text-transform: uppercase;
  font-weight: 600; font-family: var(--sans, system-ui);
  background: transparent; color: var(--yellow, #f5c518);
  border: 1px solid var(--yellow, #f5c518);
  cursor: pointer; transition: all 0.18s;
  border-radius: 2px;
}
.fr-focus-btn:hover { background: var(--yellow, #f5c518); color: #0a0a0a; }
.fr-focus-btn.active {
  background: var(--yellow, #f5c518); color: #0a0a0a;
  box-shadow: 0 0 0 2px rgba(245,197,24,0.3), 0 0 14px rgba(245,197,24,0.45);
}

/* "More details" link on the back of each flashcard */
.fr-details-row {
  margin-top: 0.9rem; padding-top: 0.7rem;
  border-top: 1px dashed var(--gray-border, #252525);
  text-align: right;
}
.fr-details-link {
  display: inline-block;
  font-size: 0.72rem; letter-spacing: 0.06em;
  color: var(--yellow, #f5c518); text-decoration: none;
  padding: 0.25rem 0.6rem; border: 1px solid rgba(245,197,24,0.25);
  transition: all 0.15s;
}
.fr-details-link:hover {
  background: var(--yellow, #f5c518); color: #0a0a0a;
  border-color: var(--yellow, #f5c518);
}

/* Overall progress (picker header) */
.fr-overall {
  display: grid; grid-template-columns: 1.1fr 2fr 0.9fr 0.9fr;
  gap: 1rem; align-items: center;
  padding: 0.9rem 1.1rem;
  background: rgba(245,197,24,0.04);
  border: 1px solid rgba(245,197,24,0.22);
}
.fr-overall-stat { display: flex; flex-direction: column; align-items: flex-start; gap: 0.15rem; }
.fr-overall-v {
  font-size: 1.55rem; font-weight: 700; line-height: 1;
  color: var(--yellow, #f5c518); font-variant-numeric: tabular-nums;
}
.fr-overall-of { font-size: 0.9rem; font-weight: 400; color: var(--gray, #888); margin-left: 0.1rem; }
.fr-overall-l {
  font-size: 0.58rem; letter-spacing: 0.14em; text-transform: uppercase;
  color: var(--gray, #888); font-weight: 600;
}
.fr-overall-stat.danger .fr-overall-v { color: #e84545; }
.fr-overall-bar {
  grid-column: 2; align-self: center;
  height: 6px; background: var(--gray-border, #252525); overflow: hidden;
}
.fr-overall-fill {
  height: 100%; background: var(--yellow, #f5c518);
  transition: width 0.6s cubic-bezier(.2,.8,.2,1);
}
@media (max-width: 640px) {
  .fr-overall { grid-template-columns: 1fr 1fr; }
  .fr-overall-bar { grid-column: 1 / -1; order: 99; }
}

/* Topic description on picker tile */
.fr-topic-card .ft-desc {
  margin-top: 0.3rem;
  font-size: 0.72rem; line-height: 1.45;
  color: var(--gray, #888);
  font-weight: 300;
  display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical;
  overflow: hidden;
}

/* Card title — clickable when it links to the concept modal */
.fr-card-title.clickable { cursor: pointer; }
.fr-card-title.clickable:hover {
  color: var(--yellow, #f5c518);
}
.fr-card-title-ico {
  font-size: 0.68em; opacity: 0.55;
  margin-left: 0.25em; vertical-align: super;
}

/* Keyword chip — native tooltip on hover, click opens concept modal */
.fr-kw-chip {
  cursor: pointer;
  transition: background 0.12s, color 0.12s, border-color 0.12s;
}
.fr-kw-chip:hover {
  background: rgba(245,197,24,0.12);
  border-color: var(--yellow, #f5c518) !important;
  color: var(--yellow, #f5c518);
}

/* Remove legacy fr-details-link — kept hidden for older cached HTML */
.fr-details-row { display: none !important; }