/* ═══════════════════════════════════════════════════════
   COMPONENTS.CSS — Buttons, Cards, Badges, Flashcard,
   Modals, Toasts, Pills, Select, Toggle, Quiz, Cheatsheet
═══════════════════════════════════════════════════════ */

/* ── BUTTONS ──────────────────────────────────────── */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  gap: 6px; padding: 9px 18px; border-radius: var(--r);
  font-family: var(--font-mono); font-size: .75rem;
  font-weight: 700; letter-spacing: .05em;
  border: 1px solid transparent;
  transition: all var(--fast) var(--ease);
  cursor: pointer; white-space: nowrap; user-select: none;
}
.btn:disabled { opacity: .45; cursor: not-allowed; }

.btn-primary {
  background: var(--green); color: #050a06;
  border-color: var(--green);
}
.btn-primary:hover:not(:disabled) { background: #5dff92; border-color: #5dff92; }

.btn-accent {
  background: rgba(var(--accent-rgb),.12);
  color: var(--accent, var(--green));
  border-color: rgba(var(--accent-rgb),.3);
}
.btn-accent:hover:not(:disabled) {
  background: rgba(var(--accent-rgb),.2);
  border-color: rgba(var(--accent-rgb),.5);
}

.btn-ghost {
  background: transparent; color: var(--text-dim);
  border-color: var(--border);
}
.btn-ghost:hover:not(:disabled) {
  color: var(--text); border-color: var(--border-2);
  background: var(--card);
}

.btn-danger {
  background: rgba(255,77,106,.1); color: var(--red);
  border-color: rgba(255,77,106,.3);
}
.btn-danger:hover:not(:disabled) { background: rgba(255,77,106,.2); }

.btn-sm  { padding: 5px 12px; font-size: .7rem; border-radius: var(--r-sm); }
.btn-lg  { padding: 12px 28px; font-size: .85rem; }
.btn-icon { padding: 8px; border-radius: var(--r-sm); min-width: 34px; }

/* Rating buttons */
.btn-forgot { background: rgba(255,77,106,.1);  color: var(--red);    border-color: rgba(255,77,106,.25); }
.btn-fuzzy  { background: rgba(255,229,102,.1); color: var(--yellow); border-color: rgba(255,229,102,.25); }
.btn-got    { background: var(--green-bg);       color: var(--green);  border-color: var(--green-dim); }
.btn-forgot:hover { background: rgba(255,77,106,.2); }
.btn-fuzzy:hover  { background: rgba(255,229,102,.2); }
.btn-got:hover    { background: rgba(61,255,122,.15); }

/* ── PILLS / TAGS ─────────────────────────────────── */
.pill {
  display: inline-flex; align-items: center; gap: 4px;
  padding: 4px 12px; border-radius: 20px;
  font-family: var(--font-mono); font-size: .68rem;
  font-weight: 500; border: 1px solid var(--border);
  background: var(--card); color: var(--text-dim);
  cursor: pointer; transition: all var(--fast) var(--ease);
  user-select: none; white-space: nowrap;
}
.pill:hover { border-color: var(--border-2); color: var(--text); }
.pill.active {
  background: rgba(var(--accent-rgb, 61,255,122),.1);
  border-color: rgba(var(--accent-rgb, 61,255,122),.4);
  color: var(--accent, var(--green));
}
.pill-static { cursor: default; }
.pill-static:hover { border-color: var(--border); color: var(--text-dim); }

/* ── DIFFICULTY BADGE ─────────────────────────────── */
.diff-badge {
  display: inline-flex; align-items: center;
  padding: 2px 9px; border-radius: 12px;
  font-family: var(--font-mono); font-size: .62rem;
  font-weight: 700; letter-spacing: .07em;
  text-transform: uppercase;
  color: var(--dc); border: 1px solid var(--dc);
  background: rgba(var(--dc-rgb, 61,255,122),.08);
}
.diff-badge.d1 { --dc: var(--d1); }
.diff-badge.d2 { --dc: var(--d2); }
.diff-badge.d3 { --dc: var(--d3); }
.diff-badge.d4 { --dc: var(--d4); }
.diff-badge.d5 { --dc: var(--d5); }

/* ── TOPIC CARD (dashboard) ───────────────────────── */
.topic-card {
  background: var(--card); border: 1px solid var(--border);
  border-radius: var(--r-xl); padding: 22px 24px;
  cursor: pointer; transition: all var(--med) var(--ease);
  position: relative; overflow: hidden;
  display: flex; flex-direction: column; gap: 14px;
  text-decoration: none; color: inherit;
}
.topic-card::before {
  content: '';
  position: absolute; top: 0; left: 0; right: 0; height: 2px;
  background: var(--accent, var(--green));
  opacity: 0; transition: opacity var(--fast);
}
.topic-card:hover {
  border-color: rgba(var(--accent-rgb,61,255,122),.3);
  background: var(--card-hover);
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}
.topic-card:hover::before { opacity: 1; }

.topic-card-header {
  display: flex; align-items: center;
  justify-content: space-between; gap: var(--gap-sm);
}
.topic-card-icon {
  width: 44px; height: 44px;
  border-radius: var(--r);
  background: rgba(var(--accent-rgb,61,255,122),.08);
  border: 1px solid rgba(var(--accent-rgb,61,255,122),.2);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.3rem; flex-shrink: 0;
}
.topic-card-title {
  font-family: var(--font-display);
  font-size: .85rem; font-weight: 700;
  color: var(--text-bright); flex: 1;
  margin-top: 10px;
}
.topic-card-meta {
  font-size: .68rem; color: var(--text-dim);
  display: flex; gap: var(--gap-sm); flex-wrap: wrap;
}
.topic-card-meta span { display: flex; align-items: center; gap: 3px; }
.topic-card-meta .starred { color: var(--star); }

.topic-card-progress { }
.topic-card-progress-header {
  display: flex; justify-content: space-between;
  font-size: .65rem; color: var(--text-dim);
  margin-bottom: 6px;
}
.topic-card-progress-pct {
  font-family: var(--font-mono); font-weight: 700;
  color: var(--accent, var(--green));
}

.topic-card-actions {
  display: flex; gap: var(--gap-sm); margin-top: 4px;
}
.topic-card-actions .btn { flex: 1; font-size: .68rem; padding: 7px 10px; }

/* ── FLASHCARD (generic — study.html overrides axis inline) ─── */
.fc-wrap { perspective: 1200px; margin-bottom: 14px; }
.card-face {
  position: absolute; inset: 0;
  background: var(--card); border: 1px solid var(--border);
  border-radius: var(--r-xl); padding: 40px 48px;
  backface-visibility: hidden;
  display: flex; flex-direction: column;
  align-items: center; justify-content: center;
  text-align: center; transition: border-color var(--fast);
}
.card-face:hover { border-color: var(--border-2); }
.card-front { }
.card-back  { transform: rotateY(180deg); }

/* Accent line on card */
.card-face::after {
  content: '';
  position: absolute; top: 0; left: 10%; right: 10%; height: 1px;
  background: linear-gradient(90deg, transparent, rgba(var(--accent-rgb,61,255,122),.3), transparent);
}

.card-topic-tag {
  font-family: var(--font-mono); font-size: .62rem;
  letter-spacing: .12em; text-transform: uppercase;
  color: var(--accent, var(--green)); opacity: .7;
  margin-bottom: 12px;
}
.card-question {
  font-family: var(--font-mono); font-size: 1.05rem;
  font-weight: 500; line-height: 1.65;
  color: var(--text-bright); max-width: 640px;
}
.card-hint {
  margin-top: 20px; font-size: .68rem;
  color: var(--text-muted); letter-spacing: .06em;
  font-family: var(--font-mono);
}
.card-answer {
  font-family: var(--font-mono); font-size: .9rem;
  line-height: 1.8; color: var(--accent, var(--green));
  text-align: left; white-space: pre-wrap;
  max-width: 680px; width: 100%;
}
.card-interview-flag {
  position: absolute; top: 16px; right: 16px;
  background: rgba(255,140,66,.12); border: 1px solid rgba(255,140,66,.3);
  color: var(--orange); font-size: .6rem; letter-spacing: .08em;
  padding: 3px 8px; border-radius: 12px; font-family: var(--font-mono);
  text-transform: uppercase; font-weight: 700;
}

/* Star button on card */
.card-star-btn {
  position: absolute; top: 14px; left: 16px;
  width: 30px; height: 30px; border-radius: var(--r-sm);
  display: flex; align-items: center; justify-content: center;
  font-size: 1rem; color: var(--text-muted);
  background: transparent; border: 1px solid transparent;
  transition: all var(--fast); cursor: pointer; z-index: 2;
}
.card-star-btn:hover { color: var(--star); background: rgba(255,193,7,.08); border-color: rgba(255,193,7,.2); }
.card-star-btn.starred { color: var(--star); animation: starPop .25s var(--ease); }

/* Card controls */
.card-controls {
  display: flex; gap: var(--gap-sm);
  justify-content: center; flex-wrap: wrap;
  margin-bottom: 10px;
}

/* ── EXPLANATION PANEL ────────────────────────────── */
.explain-panel {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--r-lg); overflow: hidden;
  margin-bottom: 14px; display: none;
}
.explain-panel.open { display: block; animation: fadeUp var(--med) var(--ease); }
.explain-tabs {
  display: flex; border-bottom: 1px solid var(--border);
}
.explain-tab {
  padding: 10px 18px; font-size: .72rem;
  font-family: var(--font-mono); color: var(--text-dim);
  border-bottom: 2px solid transparent;
  cursor: pointer; transition: all var(--fast);
  margin-bottom: -1px; letter-spacing: .04em;
}
.explain-tab:hover { color: var(--text); }
.explain-tab.active { color: var(--accent, var(--green)); border-bottom-color: var(--accent, var(--green)); }
.explain-body {
  padding: 20px 24px; display: none;
}
.explain-body.active { display: block; animation: fadeIn var(--fast); }
.explain-text {
  font-size: .82rem; line-height: 1.8;
  color: var(--text); font-family: var(--font-body);
}
.example-block {
  background: var(--card); border: 1px solid var(--border);
  border-radius: var(--r); padding: 16px 20px; margin-top: 14px;
}
.example-label {
  font-size: .6rem; letter-spacing: .1em;
  text-transform: uppercase; color: var(--text-muted);
  font-family: var(--font-mono); margin-bottom: 10px;
}
.example-code {
  font-family: var(--font-mono); font-size: .8rem;
  color: var(--green); line-height: 1.9; white-space: pre-wrap;
}
.example-code .comment { color: var(--text-muted); }
.interview-tip {
  background: rgba(255,140,66,.06);
  border: 1px solid rgba(255,140,66,.2);
  border-radius: var(--r); padding: 14px 18px;
  font-size: .82rem; line-height: 1.8; color: var(--text);
}
.interview-tip-label {
  font-size: .6rem; color: var(--orange); letter-spacing: .1em;
  text-transform: uppercase; font-family: var(--font-mono);
  font-weight: 700; margin-bottom: 8px;
  display: flex; align-items: center; gap: 6px;
}

/* ── FC META BAR ──────────────────────────────────── */
.fc-meta-bar {
  display: flex; align-items: center;
  justify-content: space-between; gap: var(--gap-sm);
  margin-bottom: 10px; flex-wrap: wrap;
}
.fc-counter {
  font-family: var(--font-mono); font-size: .72rem; color: var(--text-dim);
}
.fc-badges { display: flex; gap: 6px; align-items: center; }
.level-dots {
  display: flex; gap: 3px; align-items: center;
}
.level-dot {
  width: 7px; height: 7px; border-radius: 50%;
  background: var(--border); transition: background var(--fast);
}
.level-dot.on { background: var(--dc, var(--green)); }

/* ── SELECT ───────────────────────────────────────── */
.select {
  background: var(--card); border: 1px solid var(--border);
  color: var(--text); padding: 7px 12px; border-radius: var(--r);
  font-family: var(--font-mono); font-size: .72rem;
  cursor: pointer; outline: none;
  transition: border-color var(--fast);
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6' viewBox='0 0 10 6'%3E%3Cpath d='M1 1l4 4 4-4' stroke='%233d5c70' stroke-width='1.5' fill='none' stroke-linecap='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 10px center;
  padding-right: 28px;
}
.select:focus { border-color: var(--border-2); }
.select:hover { border-color: var(--border-2); }

/* ── TOGGLE SWITCH ────────────────────────────────── */
.toggle-wrap {
  display: flex; align-items: center; gap: 8px;
  cursor: pointer; user-select: none;
}
.toggle-wrap input { display: none; }
.toggle {
  width: 34px; height: 18px; border-radius: 9px;
  background: var(--border-2); position: relative;
  transition: background var(--fast);
  flex-shrink: 0;
}
.toggle::after {
  content: '';
  position: absolute; top: 2px; left: 2px;
  width: 14px; height: 14px; border-radius: 50%;
  background: var(--text-dim);
  transition: all var(--fast) var(--ease);
}
.toggle-wrap input:checked + .toggle { background: var(--accent, var(--green)); }
.toggle-wrap input:checked + .toggle::after {
  left: 18px; background: #fff;
}
.toggle-label {
  font-size: .72rem; color: var(--text-dim);
  font-family: var(--font-mono); letter-spacing: .04em;
}

/* ── SEARCH INPUT ─────────────────────────────────── */
.search-wrap { position: relative; }
.search-icon {
  position: absolute; left: 12px; top: 50%; transform: translateY(-50%);
  color: var(--text-muted); font-size: .9rem; pointer-events: none;
}
.search-input {
  width: 100%; background: var(--card);
  border: 1px solid var(--border); border-radius: var(--r);
  padding: 10px 14px 10px 36px;
  color: var(--text); font-family: var(--font-mono); font-size: .8rem;
  outline: none; transition: border-color var(--fast);
}
.search-input:focus { border-color: var(--border-2); }
.search-input::placeholder { color: var(--text-muted); }

/* ── QUIZ ─────────────────────────────────────────── */
.quiz-q-card {
  background: var(--card); border: 1px solid var(--border);
  border-radius: var(--r-xl); padding: 32px 36px;
  margin-bottom: 16px; animation: fadeUp var(--med) var(--ease);
}
.quiz-q-text {
  font-family: var(--font-mono); font-size: 1rem;
  font-weight: 500; line-height: 1.7;
  color: var(--text-bright); margin-bottom: 24px;
}
.quiz-opts { display: flex; flex-direction: column; gap: 8px; }
.quiz-opt {
  padding: 13px 18px; border-radius: var(--r);
  border: 1px solid var(--border); background: var(--surface);
  cursor: pointer; font-family: var(--font-mono);
  font-size: .82rem; color: var(--text); line-height: 1.5;
  transition: all var(--fast) var(--ease); text-align: left;
}
.quiz-opt:hover:not(:disabled) {
  border-color: var(--border-2); background: var(--card);
}
.quiz-opt.correct { border-color: var(--green); background: var(--green-bg); color: var(--green); }
.quiz-opt.wrong   { border-color: var(--red);   background: rgba(255,77,106,.07); color: var(--red); }
.quiz-opt.shown   { border-color: var(--green-dim); color: var(--text-dim); }
.quiz-opt:disabled { cursor: default; }

.quiz-score-card {
  background: var(--card); border: 1px solid var(--border);
  border-radius: var(--r-xl); padding: 56px 32px; text-align: center;
  animation: fadeUp var(--med) var(--ease);
}
.quiz-score-pct {
  font-family: var(--font-display); font-size: 5rem;
  font-weight: 900; line-height: 1; margin-bottom: 6px;
}
.quiz-score-label { color: var(--text-dim); font-size: .85rem; margin-bottom: 28px; }
.quiz-score-breakdown {
  display: flex; justify-content: center; gap: var(--gap-lg);
  margin-bottom: 32px; flex-wrap: wrap;
}
.quiz-score-stat { text-align: center; }
.quiz-score-stat-val {
  font-family: var(--font-display); font-size: 1.5rem; font-weight: 700;
}
.quiz-score-stat-label { font-size: .65rem; color: var(--text-dim); letter-spacing: .08em; text-transform: uppercase; font-family: var(--font-mono); }

/* ── CHEATSHEET ───────────────────────────────────── */
.cheat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: var(--gap);
}
.cheat-section {
  background: var(--card); border: 1px solid var(--border);
  border-radius: var(--r-lg); padding: 18px 20px;
  transition: border-color var(--fast);
}
.cheat-section:hover { border-color: var(--border-2); }
.cheat-sec-title {
  font-size: .62rem; letter-spacing: .12em; text-transform: uppercase;
  font-weight: 700; margin-bottom: 12px;
  padding-bottom: 10px; border-bottom: 1px solid var(--border);
  font-family: var(--font-mono);
}
.cheat-row {
  display: flex; justify-content: space-between;
  align-items: flex-start; padding: 6px 0;
  border-bottom: 1px solid var(--border); gap: 12px;
  transition: background var(--fast);
}
.cheat-row:last-child { border-bottom: none; }
.cheat-row.hl { background: rgba(61,255,122,.04); margin: 0 -20px; padding: 6px 20px; }
.cheat-cmd {
  font-family: var(--font-mono); font-size: .78rem;
  color: var(--accent, var(--green)); white-space: nowrap;
  cursor: pointer; transition: color var(--fast);
  flex-shrink: 0;
}
.cheat-cmd:hover { color: #fff; }
.cheat-desc { font-size: .72rem; color: var(--text-dim); text-align: right; line-height: 1.4; }

/* ── STAR LIST (progress page) ────────────────────── */
.star-card {
  background: var(--card); border: 1px solid rgba(255,193,7,.15);
  border-radius: var(--r-lg); padding: 14px 18px;
  display: flex; align-items: flex-start;
  justify-content: space-between; gap: var(--gap-sm);
}
.star-card-q { font-size: .82rem; color: var(--text); flex: 1; line-height: 1.5; }
.star-card-meta { display: flex; gap: 6px; align-items: center; flex-shrink: 0; }

/* ── STRUGGLE CARD ────────────────────────────────── */
.struggle-card {
  background: var(--card); border: 1px solid rgba(255,77,106,.12);
  border-radius: var(--r-lg); padding: 12px 16px;
  display: flex; align-items: center; gap: var(--gap-sm);
}
.struggle-q { font-size: .8rem; color: var(--text); flex: 1; }
.struggle-badge {
  font-size: .65rem; color: var(--red);
  border: 1px solid rgba(255,77,106,.25); border-radius: 12px;
  padding: 2px 8px; white-space: nowrap; font-family: var(--font-mono);
}

/* ── TOAST ────────────────────────────────────────── */
#toast-container {
  position: fixed; bottom: 24px; right: 24px;
  z-index: 1000; display: flex; flex-direction: column; gap: 8px;
}
.toast {
  background: var(--card-2); border: 1px solid var(--border-2);
  color: var(--text); padding: 10px 18px; border-radius: var(--r);
  font-size: .78rem; font-family: var(--font-mono);
  display: flex; align-items: center; gap: 8px;
  box-shadow: var(--shadow);
  animation: toastIn .2s var(--ease);
  max-width: 320px;
}
.toast.success { border-color: var(--green-dim); color: var(--green); }
.toast.error   { border-color: rgba(255,77,106,.3); color: var(--red); }
.toast.star    { border-color: rgba(255,193,7,.3); color: var(--star); }
.toast.out     { animation: toastOut .3s var(--ease) forwards; }

/* ── MODAL ────────────────────────────────────────── */
.modal-overlay {
  position: fixed; inset: 0; z-index: 200;
  background: rgba(0,0,0,.7); backdrop-filter: blur(4px);
  display: flex; align-items: center; justify-content: center;
  padding: 20px; animation: fadeIn var(--fast);
}
.modal {
  background: var(--card); border: 1px solid var(--border-2);
  border-radius: var(--r-xl); padding: 32px 36px;
  max-width: 520px; width: 100%;
  box-shadow: var(--shadow-lg);
  animation: fadeUp var(--med) var(--ease);
}
.modal-title {
  font-family: var(--font-display); font-size: 1rem; font-weight: 700;
  color: var(--text-bright); margin-bottom: 20px;
}
.modal-actions { display: flex; gap: var(--gap-sm); justify-content: flex-end; margin-top: 24px; }

/* ── EMPTY STATE ──────────────────────────────────── */
.empty-state {
  text-align: center; padding: 60px 24px;
  background: var(--card); border: 1px solid var(--border);
  border-radius: var(--r-xl);
}
.empty-state-icon { font-size: 2.5rem; margin-bottom: 12px; }
.empty-state-title {
  font-family: var(--font-display); font-size: 1rem;
  font-weight: 700; color: var(--text-bright); margin-bottom: 8px;
}
.empty-state-sub { font-size: .82rem; color: var(--text-dim); margin-bottom: 24px; }

/* ── KEYBOARD HINTS ───────────────────────────────── */
.kbd-hints {
  display: flex; gap: var(--gap); justify-content: center;
  flex-wrap: wrap; margin-top: 12px;
}
.kbd-hint {
  display: flex; align-items: center; gap: 5px;
  font-size: .65rem; color: var(--text-muted); font-family: var(--font-mono);
}
kbd {
  display: inline-flex; align-items: center; justify-content: center;
  min-width: 22px; height: 18px; padding: 0 4px;
  background: var(--card); border: 1px solid var(--border-2);
  border-bottom-width: 2px; border-radius: 3px;
  font-family: var(--font-mono); font-size: .6rem; color: var(--text-dim);
}

/* ── RESPONSIVE ───────────────────────────────────── */
@media (max-width: 768px) {
  .card-face { padding: 24px 22px; }
  .quiz-q-card { padding: 20px; }
  .cheat-grid { grid-template-columns: 1fr; }
  .modal { padding: 24px 20px; }
}
@media (max-width: 480px) {
  .topic-card-actions { flex-direction: column; }
  .card-question { font-size: .92rem; }
  .card-answer   { font-size: .82rem; }
}

/* ── PROGRESS RING ────────────────────────────────── */
.progress-ring {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.progress-ring svg {
  position: absolute;
  top: 0; left: 0;
  transform: rotate(-90deg);
}
.progress-ring-text {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  width: 100%;
  height: 100%;
}
.ring-pct {
  font-family: var(--font-mono);
  font-size: .65rem;
  font-weight: 700;
  color: var(--green);
  line-height: 1;
}

/* ── LEVEL DOTS ───────────────────────────────────── */
.level-dots {
  display: flex; gap: 3px; align-items: center;
}
.level-dot {
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--border-2);
  transition: background var(--fast) var(--ease);
}