/* ========================================
   Minna Cards — Design System & Styles
   Dark Japanese-inspired theme
   ======================================== */

/* --- CSS Custom Properties --- */
:root {
  /* Background layers */
  --bg-deep: #0f0f1a;
  --bg-base: #1a1a2e;
  --bg-surface: #24243e;
  --bg-elevated: #2d2d4a;

  /* Accent — warm vermillion (torii red) */
  --accent: #e74c3c;
  --accent-hover: #ff6b5a;
  --accent-glow: rgba(231, 76, 60, 0.25);
  --accent-subtle: rgba(231, 76, 60, 0.1);

  /* Text */
  --text-primary: #f0e6d3;
  --text-secondary: #a89f91;
  --text-muted: #6b6358;
  --text-inverse: #1a1a2e;

  /* Feedback */
  --correct: #2ecc71;
  --correct-glow: rgba(46, 204, 113, 0.2);
  --correct-bg: rgba(46, 204, 113, 0.08);
  --wrong: #e74c3c;
  --wrong-glow: rgba(231, 76, 60, 0.2);
  --wrong-bg: rgba(231, 76, 60, 0.08);

  /* Borders */
  --border-subtle: rgba(255, 255, 255, 0.06);
  --border-medium: rgba(255, 255, 255, 0.1);

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;

  /* Radius */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 24px;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 400ms ease;

  /* Font */
  --font-family: 'Noto Sans JP', -apple-system, BlinkMacSystemFont, sans-serif;
}

/* --- Reset & Base --- */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-family);
  background: var(--bg-deep);
  color: var(--text-primary);
  min-height: 100dvh;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: var(--space-md);
  overflow-x: hidden;

  /* Subtle radial gradient background */
  background: radial-gradient(ellipse at 50% 0%, #1e1e3a 0%, var(--bg-deep) 70%);
}

/* --- Screen Management --- */
.screen {
  width: 100%;
  max-width: 480px;
  animation: fadeIn var(--transition-slow) ease forwards;
}

.screen.hidden,
.hidden {
  display: none !important;
}

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

/* --- App Header --- */
.app-header {
  text-align: center;
  margin-bottom: var(--space-2xl);
}

.app-title {
  font-size: 2.5rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, var(--text-primary) 0%, var(--accent) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: var(--space-xs);
}

.app-subtitle {
  font-size: 0.875rem;
  color: var(--text-secondary);
  font-weight: 300;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

/* --- Setup Card --- */
.setup-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  display: flex;
  flex-direction: column;
  gap: var(--space-xl);
}

.setup-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.setup-label {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

/* --- Chip Group (Chapter & Mode selectors) --- */
.chip-group {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 0.6rem 1rem;
  background: var(--bg-elevated);
  border: 1px solid var(--border-medium);
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  font-family: var(--font-family);
  font-size: 0.875rem;
  font-weight: 400;
  cursor: pointer;
  transition: all var(--transition-fast);
  user-select: none;
  -webkit-tap-highlight-color: transparent;
}

.chip:hover {
  border-color: var(--accent);
  color: var(--text-primary);
  background: var(--accent-subtle);
}

.chip.selected {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-subtle);
  font-weight: 500;
  box-shadow: 0 0 12px var(--accent-glow);
}

.chip-icon {
  font-weight: 600;
  font-size: 0.8rem;
}

.chip-text {
  white-space: nowrap;
}

/* --- Word Count Row --- */
.word-count-row {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.word-count-input {
  width: 72px;
  padding: 0.5rem 0.75rem;
  background: var(--bg-elevated);
  border: 1px solid var(--border-medium);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-family: var(--font-family);
  font-size: 1rem;
  font-weight: 500;
  text-align: center;
  transition: border-color var(--transition-fast);
  -moz-appearance: textfield;
}

.word-count-input::-webkit-inner-spin-button,
.word-count-input::-webkit-outer-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.word-count-input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 8px var(--accent-glow);
}

.word-count-total {
  color: var(--text-muted);
  font-size: 0.875rem;
}

/* --- Buttons --- */
.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.75rem 1.5rem;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: var(--radius-md);
  font-family: var(--font-family);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-fast);
  user-select: none;
  -webkit-tap-highlight-color: transparent;
}

.btn-primary:hover:not(:disabled) {
  background: var(--accent-hover);
  box-shadow: 0 4px 20px var(--accent-glow);
  transform: translateY(-1px);
}

.btn-primary:active:not(:disabled) {
  transform: translateY(0);
}

.btn-primary:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.75rem 1.5rem;
  background: transparent;
  color: var(--text-secondary);
  border: 1px solid var(--border-medium);
  border-radius: var(--radius-md);
  font-family: var(--font-family);
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
  user-select: none;
  -webkit-tap-highlight-color: transparent;
}

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

.btn-ghost {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  padding: 0;
  background: transparent;
  color: var(--text-muted);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  font-size: 1rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  -webkit-tap-highlight-color: transparent;
}

.btn-ghost:hover {
  color: var(--text-primary);
  border-color: var(--border-medium);
  background: var(--bg-elevated);
}

/* --- Quiz Header --- */
.quiz-header {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
}

.progress-indicator {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.progress-text {
  font-size: 0.8rem;
  color: var(--text-secondary);
  font-weight: 400;
}

.progress-text.review-mode {
  color: var(--accent);
}

.progress-bar-track {
  width: 100%;
  height: 3px;
  background: var(--bg-elevated);
  border-radius: 2px;
  overflow: hidden;
}

.progress-bar-fill {
  height: 100%;
  background: var(--accent);
  border-radius: 2px;
  transition: width var(--transition-base);
  width: 0%;
}

.mode-badge {
  font-size: 0.7rem;
  font-weight: 600;
  padding: 0.3rem 0.6rem;
  background: var(--accent-subtle);
  color: var(--accent);
  border-radius: var(--radius-sm);
  border: 1px solid rgba(231, 76, 60, 0.2);
  white-space: nowrap;
}

/* --- Prompt Card --- */
.prompt-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: var(--space-2xl) var(--space-xl);
  text-align: center;
  margin-bottom: var(--space-xl);
  min-height: 140px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
}

.prompt-text {
  font-size: 2rem;
  font-weight: 600;
  line-height: 1.3;
  word-break: break-word;
}

.prompt-kanji {
  font-size: 1rem;
  color: var(--text-muted);
  font-weight: 300;
}

/* --- Answer Area --- */
.answer-area {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.answer-input {
  width: 100%;
  padding: 0.875rem 0;
  background: transparent;
  border: none;
  border-bottom: 2px solid var(--border-medium);
  color: var(--text-primary);
  font-family: var(--font-family);
  font-size: 1.25rem;
  font-weight: 400;
  text-align: center;
  transition: border-color var(--transition-fast);
  caret-color: var(--accent);
}

.answer-input::placeholder {
  color: var(--text-muted);
  font-weight: 300;
}

.answer-input:focus {
  outline: none;
  border-bottom-color: var(--accent);
}

.answer-buttons {
  display: flex;
  gap: var(--space-sm);
}

.answer-buttons .btn-secondary {
  flex: 1;
}

.answer-buttons .btn-primary {
  flex: 2;
}

/* --- Result Overlay --- */
.result-overlay {
  position: fixed;
  inset: 0;
  background: rgba(15, 15, 26, 0.85);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  display: flex;
  justify-content: center;
  align-items: center;
  padding: var(--space-md);
  z-index: 100;
  animation: overlayIn var(--transition-base) ease forwards;
}

.result-overlay.hidden {
  display: none !important;
}

@keyframes overlayIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}

.result-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: var(--space-xl) var(--space-xl) var(--space-lg);
  text-align: center;
  width: 100%;
  max-width: 400px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-md);
  animation: cardIn var(--transition-base) ease forwards;
}

@keyframes cardIn {
  from { opacity: 0; transform: scale(0.95) translateY(8px); }
  to   { opacity: 1; transform: scale(1) translateY(0); }
}

.result-card.correct {
  border-color: var(--correct);
  box-shadow: 0 0 30px var(--correct-glow);
}

.result-card.wrong {
  border-color: var(--wrong);
  box-shadow: 0 0 30px var(--wrong-glow);
}

.result-icon {
  font-size: 2.5rem;
  line-height: 1;
}

.result-label {
  font-size: 1.125rem;
  font-weight: 600;
}

.result-card.correct .result-label {
  color: var(--correct);
}

.result-card.wrong .result-label {
  color: var(--wrong);
}

.result-answer {
  font-size: 1.75rem;
  font-weight: 600;
}

.result-kanji {
  font-size: 1rem;
  color: var(--text-muted);
}

.result-user-input {
  font-size: 0.9rem;
  color: var(--text-secondary);
  background: var(--wrong-bg);
  border: 1px solid rgba(231, 76, 60, 0.25);
  border-radius: var(--radius-md);
  padding: var(--space-xs) var(--space-md);
  max-width: 100%;
  word-break: break-word;
  text-align: center;
}

.result-user-input.hidden {
  display: none !important;
}

.result-user-input .typed-text {
  color: var(--wrong);
  font-style: italic;
  font-weight: 600;
  margin-left: 2px;
}

.result-user-input.skipped {
  color: var(--text-muted);
  font-style: italic;
  border-style: dashed;
}

.result-alts {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.result-alts .alt-heading {
  font-weight: 500;
  color: var(--text-muted);
  margin-bottom: var(--space-xs);
}

.continue-hint {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: calc(-1 * var(--space-sm));
}

/* --- Results Screen --- */
.results-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: var(--space-2xl);
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-lg);
}

.results-header {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-xs);
}

.results-icon {
  font-size: 3rem;
}

.results-title {
  font-size: 1.5rem;
  font-weight: 600;
}

.results-subtitle {
  font-size: 0.95rem;
  color: var(--text-secondary);
  font-weight: 400;
}

.results-score {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--accent);
}

.results-detail {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* --- Responsive --- */
@media (max-width: 400px) {
  .app-title {
    font-size: 2rem;
  }

  .prompt-text {
    font-size: 1.5rem;
  }

  .chip {
    padding: 0.5rem 0.75rem;
    font-size: 0.8rem;
  }

  .setup-card {
    padding: var(--space-lg);
  }
}

/* --- Action Fork (Study / Quiz) --- */
.action-fork {
  display: flex;
  gap: var(--space-sm);
}

.action-fork.hidden {
  display: none;
}

.action-fork .btn-secondary,
.action-fork .btn-primary {
  flex: 1;
}

/* --- Quiz Options (collapsible) --- */
.quiz-options {
  display: flex;
  flex-direction: column;
  gap: var(--space-xl);
  animation: fadeIn var(--transition-base) ease forwards;
}

.quiz-options.hidden {
  display: none;
}

/* --- Study Screen --- */
.study-header {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  margin-bottom: var(--space-lg);
}

.study-title {
  flex: 1;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
}

.study-page-info {
  font-size: 0.8rem;
  color: var(--text-muted);
  font-weight: 400;
}

.study-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  overflow: hidden;
  margin-bottom: var(--space-lg);
}

.study-table thead {
  background: var(--bg-elevated);
}

.study-table th {
  padding: 0.6rem 0.75rem;
  font-size: 0.7rem;
  font-weight: 500;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  text-align: left;
}

.study-table td {
  padding: 0.75rem;
  font-size: 0.9rem;
  color: var(--text-primary);
  border-top: 1px solid var(--border-subtle);
  vertical-align: middle;
}

.study-table tr:hover td {
  background: rgba(255, 255, 255, 0.02);
}

.study-table .kanji-cell {
  color: var(--text-muted);
  font-size: 0.85rem;
}

.study-table .no-kanji {
  color: var(--text-muted);
  opacity: 0.4;
  font-style: italic;
  font-size: 0.8rem;
}

.study-pagination {
  display: flex;
  gap: var(--space-sm);
}

.study-pagination .btn-secondary {
  flex: 1;
}

/* --- Setup Hero (first viewport) --- */
.setup-hero {
  min-height: calc(100dvh - 2 * var(--space-md)); /* body has --space-md padding */
  display: flex;
  flex-direction: column;
}

.setup-hero > .app-header {
  margin-top: auto;
}

.app-tagline {
  margin-top: var(--space-sm);
  font-size: 0.95rem;
  font-weight: 400;
  color: var(--text-secondary);
  line-height: 1.5;
}

.about-link {
  margin-top: auto;
  align-self: center;
  padding: var(--space-lg) var(--space-md) var(--space-sm);
  font-size: 0.8rem;
  color: var(--text-muted);
  text-decoration: none;
  letter-spacing: 0.04em;
  transition: color var(--transition-fast);
}

.about-link:hover,
.about-link:focus-visible {
  color: var(--accent);
}

.about-link span {
  display: inline-block;
  animation: nudge 2s ease-in-out infinite;
}

@keyframes nudge {
  0%, 100% { transform: translateY(0); }
  50%      { transform: translateY(3px); }
}

/* --- About Section --- */
.about {
  padding: var(--space-2xl) 0 var(--space-xl);
  scroll-margin-top: var(--space-lg);
}

.about-title {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: var(--space-md);
}

.about-text {
  font-size: 0.95rem;
  line-height: 1.7;
  color: var(--text-secondary);
}

.about-text strong {
  color: var(--text-primary);
  font-weight: 500;
}

.about-subtitle {
  margin: var(--space-xl) 0 var(--space-md);
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.about-modes {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.about-mode {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: var(--space-md) var(--space-lg);
}

.about-mode dt {
  font-weight: 600;
  margin-bottom: var(--space-xs);
}

.about-mode dd {
  font-size: 0.9rem;
  line-height: 1.6;
  color: var(--text-secondary);
}

/* --- Footer --- */
.app-footer {
  padding: var(--space-lg) 0 var(--space-md);
  border-top: 1px solid var(--border-subtle);
  font-size: 0.75rem;
  color: var(--text-muted);
  text-align: center;
  line-height: 1.6;
}

/* Smooth scroll for the anchor link, respecting reduced-motion users */
@media (prefers-reduced-motion: no-preference) {
  html {
    scroll-behavior: smooth;
  }
}

@media (prefers-reduced-motion: reduce) {
  .about-link span {
    animation: none;
  }
}