/* Ensure [hidden] always wins even against CSS resets */
[hidden] { display: none !important; }

/* ── Screen transitions ──────────────────────────────────── */
.drill-screen.screen-enter {
  animation: screenEnter 0.25s ease both;
}

@keyframes screenEnter {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ── SETUP SCREEN ────────────────────────────────────────── */
.setup-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  display: flex;
  flex-direction: column;
  gap: 1.75rem;
}

.setup-heading {
  font-family: var(--font-display);
  font-size: 1.6rem;
  color: var(--accent);
  font-weight: 400;
}

.setup-section {
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
}

.setup-label {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
}

.setup-hint {
  font-size: 0.83rem;
  color: var(--text-muted);
}

.setup-error {
  background: rgba(248, 113, 113, 0.12);
  border: 1px solid rgba(248, 113, 113, 0.3);
  color: #f87171;
  border-radius: var(--radius);
  padding: 0.65rem 1rem;
  font-size: 0.85rem;
  font-family: var(--font-mono);
}

/* Family pills */
.pill-shortcuts {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.pill-group {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.pill {
  padding: 0.3rem 0.7rem;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--surface2);
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 0.82rem;
  cursor: pointer;
  transition: border-color 0.15s, color 0.15s, background 0.15s;
  user-select: none;
  line-height: 1.5;
}

.pill:hover { border-color: var(--border-hover); color: var(--text); }

.pill--active {
  background: var(--accent-dim);
  border-color: rgba(245, 200, 66, 0.4);
  color: var(--accent);
}

/* Radio pills */
.setup-radio-group {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.radio-pill {
  padding: 0.4rem 1.1rem;
  border-radius: 20px;
  border: 1px solid var(--border);
  background: var(--surface2);
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 0.82rem;
  cursor: pointer;
  transition: all 0.15s;
  line-height: 1.5;
}

.radio-pill:hover { border-color: var(--border-hover); color: var(--text); }

.radio-pill.selected {
  background: var(--accent);
  border-color: var(--accent);
  color: #0c0f1a;
}

/* Count / time sub-buttons */
.setup-subsection {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  padding-left: 0.75rem;
  border-left: 2px solid var(--border);
}

.count-btn-group {
  display: flex;
  gap: 0.4rem;
  flex-wrap: wrap;
}

.count-btn {
  padding: 0.35rem 0.85rem;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--surface2);
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  cursor: pointer;
  transition: all 0.15s;
  line-height: 1.5;
}

.count-btn:hover { border-color: var(--border-hover); color: var(--text); }
.count-btn.active { background: var(--indigo); border-color: var(--indigo); color: #fff; }

.setup-number-input {
  padding: 0.45rem 0.75rem;
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  width: 160px;
  outline: none;
  transition: border-color 0.15s;
  -moz-appearance: textfield;
}
.setup-number-input::-webkit-inner-spin-button,
.setup-number-input::-webkit-outer-spin-button { -webkit-appearance: none; }
.setup-number-input:focus { border-color: var(--border-hover); }

/* Toggle switches */
.toggle-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.toggle-switch {
  position: relative;
  display: inline-block;
  width: 40px;
  height: 22px;
  flex-shrink: 0;
  cursor: pointer;
}

.toggle-switch input { display: none; }

.toggle-track {
  position: absolute;
  inset: 0;
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 11px;
  transition: background 0.2s, border-color 0.2s;
}

.toggle-track::after {
  content: '';
  position: absolute;
  width: 16px;
  height: 16px;
  background: var(--text-muted);
  border-radius: 50%;
  top: 2px;
  left: 2px;
  transition: transform 0.2s, background 0.2s;
}

.toggle-switch input:checked + .toggle-track {
  background: var(--accent-dim);
  border-color: var(--accent);
}

.toggle-switch input:checked + .toggle-track::after {
  transform: translateX(18px);
  background: var(--accent);
}

.timeout-input-wrap {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding-top: 0.25rem;
}

.setup-start-btn {
  align-self: flex-end;
  padding: 0.75rem 2rem;
  font-size: 0.95rem;
}

/* Small button — standalone style */
.btn-sm {
  padding: 0.3rem 0.7rem;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--surface2);
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  cursor: pointer;
  transition: all 0.15s;
  line-height: 1.5;
  display: inline-flex;
  align-items: center;
}

.btn-sm:hover { border-color: var(--border-hover); color: var(--text); }

/* Size modifier when combined with .btn */
.btn.btn-sm {
  padding: 0.4rem 1rem;
  font-size: 0.8rem;
  border-radius: 6px;
}

/* ── PRACTICE SCREEN ─────────────────────────────────────── */
.practice-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1.75rem;
  padding: 0.75rem 1rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.progress-display {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text-muted);
  min-width: 80px;
}

.timer-display {
  font-family: var(--font-mono);
  font-size: 1.05rem;
  color: var(--accent);
  min-width: 64px;
  text-align: center;
}

.problem-stage {
  text-align: center;
  padding: 2.5rem 1rem 2rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 1.5rem;
}

.problem-equation {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  flex-wrap: wrap;
}

.problem-operand {
  font-family: var(--font-display);
  font-size: 5rem;
  color: var(--text);
  line-height: 1;
  min-width: 2ch;
  text-align: center;
}

.problem-op {
  font-family: var(--font-mono);
  font-size: 2.8rem;
  color: var(--text-muted);
  line-height: 1;
}

.problem-blank {
  font-family: var(--font-display);
  font-size: 5rem;
  color: var(--accent);
  line-height: 1;
}

.problem-timer {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: 0.75rem;
  min-height: 1.2em;
}

/* Answer area */
.answer-area {
  display: flex;
  justify-content: center;
}

.mc-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
  width: 100%;
  max-width: 480px;
}

.mc-btn {
  padding: 1rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  font-family: var(--font-display);
  font-size: 2.2rem;
  line-height: 1;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s, color 0.15s;
}

.mc-btn:hover:not(:disabled) {
  border-color: var(--border-hover);
  background: var(--surface2);
}

.mc-btn.answer-correct {
  background: var(--green-dim);
  border-color: var(--green);
  color: var(--green);
}

.mc-btn.answer-wrong {
  background: rgba(248, 113, 113, 0.12);
  border-color: rgba(248, 113, 113, 0.5);
  color: #f87171;
  animation: shake 0.35s ease;
}

.mc-btn:disabled { cursor: default; opacity: 0.55; }

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  20%       { transform: translateX(-6px); }
  40%       { transform: translateX(6px); }
  60%       { transform: translateX(-4px); }
  80%       { transform: translateX(4px); }
}

.manual-form {
  display: flex;
  gap: 0.75rem;
  align-items: center;
}

.manual-input {
  font-family: var(--font-display);
  font-size: 3rem;
  width: 160px;
  padding: 0.5rem 1rem;
  background: var(--surface);
  border: 2px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  text-align: center;
  outline: none;
  transition: border-color 0.15s, background 0.15s;
  -moz-appearance: textfield;
}

.manual-input::-webkit-inner-spin-button,
.manual-input::-webkit-outer-spin-button { -webkit-appearance: none; }

.manual-input:focus { border-color: var(--border-hover); }

.manual-input.answer-correct {
  border-color: var(--green);
  background: var(--green-dim);
  color: var(--green);
}

.manual-input.answer-wrong {
  border-color: rgba(248, 113, 113, 0.5);
  background: rgba(248, 113, 113, 0.12);
  animation: shake 0.35s ease;
}

/* ── DASHBOARD SCREEN ────────────────────────────────────── */
.dash-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.5rem;
}

.dash-title {
  font-family: var(--font-display);
  font-size: 1.8rem;
  font-weight: 400;
  color: var(--accent);
}

.dash-tabs {
  display: flex;
  gap: 0;
  border-bottom: 1px solid var(--border);
  margin-bottom: 1.5rem;
}

.dash-tab {
  padding: 0.6rem 1.25rem;
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 0.82rem;
  cursor: pointer;
  transition: color 0.15s, border-color 0.15s;
  margin-bottom: -1px;
}

.dash-tab:hover { color: var(--text); }
.dash-tab.active { color: var(--accent); border-bottom-color: var(--accent); }

.dash-panel { min-height: 240px; }

/* Overview */
.overview-stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.stat-block {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.stat-block--chart {
  grid-column: 1 / -1;
  flex-direction: row;
  align-items: center;
  gap: 2rem;
}

.stat-big {
  font-family: var(--font-display);
  font-size: 2.4rem;
  color: var(--text);
  line-height: 1;
}

.stat-caption {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
}

.donut-wrap {
  position: relative;
  width: 160px;
  height: 160px;
  flex-shrink: 0;
}

.donut-label {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-display);
  font-size: 1.5rem;
  color: var(--text);
  pointer-events: none;
}

.avg-time-bar {
  height: 6px;
  background: var(--surface2);
  border-radius: 3px;
  overflow: hidden;
  margin-top: 0.35rem;
}

.avg-time-bar-fill {
  height: 100%;
  background: var(--indigo);
  border-radius: 3px;
  width: 0;
  transition: width 0.6s ease;
}

/* By Table chart */
.chart-wrap {
  width: 100%;
  overflow-x: auto;
  padding-bottom: 0.5rem;
}

.chart-sort-bar {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  margin-bottom: 1rem;
  flex-wrap: wrap;
}

.chart-sort-label {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  margin-right: 0.25rem;
}

.chart-sort-btn {
  padding: 0.25rem 0.7rem;
  border-radius: 5px;
  border: 1px solid var(--border);
  background: var(--surface2);
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  cursor: pointer;
  transition: all 0.15s;
  line-height: 1.5;
}

.chart-sort-btn:hover { border-color: var(--border-hover); color: var(--text); }
.chart-sort-btn.active { background: var(--accent); border-color: var(--accent); color: #0c0f1a; }

.chart-sub-wrap {
  width: 100%;
  overflow-x: auto;
  margin-bottom: 1.25rem;
}

/* Problem log */
.log-table {
  width: 100%;
  border-collapse: collapse;
}

.log-table th {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  text-align: left;
  padding: 0.5rem 0.75rem;
  border-bottom: 1px solid var(--border);
  font-weight: 400;
}

.log-table td {
  padding: 0.5rem 0.75rem;
  border-bottom: 1px solid var(--border);
  font-family: var(--font-mono);
  font-size: 0.83rem;
  color: var(--text-muted);
}

.log-row--correct td:first-child { color: var(--green); }
.log-row--wrong td:first-child { color: #f87171; }

.time-bar-cell { min-width: 90px; }

.time-bar {
  height: 4px;
  background: var(--indigo);
  border-radius: 2px;
  margin-top: 3px;
  opacity: 0.6;
}

/* ── Retry section ───────────────────────────────────────── */
.retry-section {
  margin-top: 2rem;
  border-top: 1px solid var(--border);
  padding-top: 1.25rem;
}

.retry-heading {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
}

.retry-bar {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  flex-wrap: wrap;
  margin-bottom: 0.75rem;
}

.retry-threshold-wrap {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-left: 0.25rem;
}

.retry-threshold-input {
  width: 3rem;
  padding: 0.22rem 0.35rem;
  border: 1px solid var(--border);
  border-radius: 5px;
  background: var(--surface2);
  color: var(--text);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  text-align: center;
}

.retry-footer {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.retry-count {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--text-muted);
}

/* Past sessions */
.past-sessions-section {
  margin-top: 3rem;
  border-top: 1px solid var(--border);
  padding-top: 1.5rem;
}

.past-sessions-heading {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
}

.past-sessions-list {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.session-summary-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.75rem 1rem;
  display: flex;
  align-items: center;
  gap: 1rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-muted);
}

.session-summary-card .sc-date { flex: 1; }
.session-summary-card .sc-acc  { color: var(--green); }
.session-summary-card .sc-count { color: var(--text); }

/* ── Responsive ──────────────────────────────────────────── */
@media (max-width: 600px) {
  .setup-card { padding: 1.25rem; gap: 1.25rem; }

  .problem-operand,
  .problem-blank { font-size: 3.2rem; }

  .problem-op { font-size: 2rem; }

  .mc-btn { font-size: 1.6rem; padding: 0.8rem 0.5rem; }

  .overview-stats { grid-template-columns: 1fr; }
  .stat-block--chart { flex-direction: column; align-items: flex-start; grid-column: auto; gap: 1rem; }

  .dash-tab { padding: 0.5rem 0.75rem; font-size: 0.75rem; }

  .session-summary-card { flex-wrap: wrap; gap: 0.5rem; }
}