/* ============================================================
   CSS Custom Properties — Light Tailwind-inspired theme
   ============================================================ */
:root {
  /* Finger color palette (softened for light bg) */
  --color-left-pinky:   #fca5a5; /* red-300 */
  --color-left-ring:    #fdba74; /* orange-300 */
  --color-left-middle:  #fde047; /* yellow-300 */
  --color-left-index:   #86efac; /* green-300 */
  --color-right-index:  #7dd3fc; /* sky-300 */
  --color-right-middle: #c4b5fd; /* violet-300 */
  --color-right-ring:   #f9a8d4; /* pink-300 */
  --color-right-pinky:  #d6b4a0; /* brown-ish */
  --color-thumb:        #cbd5e1; /* slate-300 */

  /* Character state colors */
  --color-neutral:   #94a3b8;   /* slate-400 */
  --color-correct:   #16a34a;   /* green-600 */
  --color-incorrect: #dc2626;   /* red-600 */
  --color-cursor-bg: #3b82f6;   /* blue-500 */
  --color-cursor-fg: #ffffff;

  /* Surface colors */
  --bg-page:    #f8fafc;   /* slate-50 */
  --bg-card:    #ffffff;
  --bg-input:   #f1f5f9;   /* slate-100 */
  --border:     #e2e8f0;   /* slate-200 */
  --border-focus: #3b82f6; /* blue-500 */
  --text-primary:   #0f172a; /* slate-900 */
  --text-secondary: #64748b; /* slate-500 */
  --text-muted:     #94a3b8; /* slate-400 */

  /* Brand */
  --brand:       #3b82f6; /* blue-500 */
  --brand-dark:  #2563eb; /* blue-600 */
  --brand-light: #eff6ff; /* blue-50 */

  /* Layout */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,.06), 0 1px 2px rgba(0,0,0,.04);
  --shadow-md: 0 4px 12px rgba(0,0,0,.08), 0 2px 4px rgba(0,0,0,.04);
  --shadow-lg: 0 10px 30px rgba(0,0,0,.10), 0 4px 8px rgba(0,0,0,.05);

  /* Typography */
  --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', 'Courier New', monospace;
  --passage-font-size: 1.6rem;
}

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

html {
  font-size: 16px;
  min-width: 320px;
  overflow-x: hidden;
}

body {
  font-family: var(--font-sans);
  background: var(--bg-page);
  color: var(--text-primary);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
}

/* ============================================================
   Utility
   ============================================================ */
.hidden { display: none !important; }

/* Visually hidden but accessible to screen readers */
.sr-only {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
  border: 0;
}

/* ============================================================
   Buttons
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  padding: 0.5rem 1.125rem;
  border: 1.5px solid transparent;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-family: var(--font-sans);
  font-weight: 500;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s, color 0.15s, box-shadow 0.15s;
  white-space: nowrap;
}

.btn:focus-visible {
  outline: 2px solid var(--brand);
  outline-offset: 2px;
}

.btn-primary {
  background: var(--brand);
  color: #fff;
  border-color: var(--brand);
  box-shadow: 0 1px 3px rgba(59,130,246,.3);
}
.btn-primary:hover {
  background: var(--brand-dark);
  border-color: var(--brand-dark);
  box-shadow: 0 2px 6px rgba(59,130,246,.4);
}

.btn-secondary {
  background: #fff;
  color: var(--brand);
  border-color: var(--border);
}
.btn-secondary:hover {
  border-color: var(--brand);
  background: var(--brand-light);
}

.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
  border-color: transparent;
}
.btn-ghost:hover {
  background: var(--bg-input);
  color: var(--text-primary);
}

.btn-sm { padding: 0.375rem 0.75rem; font-size: 0.8rem; }

/* ============================================================
   Screens
   ============================================================ */
.screen {
  width: 100%;
  flex: 1;
  display: flex;
  flex-direction: column;
}

/* ============================================================
   Lesson Select Screen
   ============================================================ */

/* Compact inline navbar header */
.app-header {
  display: flex;
  align-items: center;
  gap: 0.625rem;
  padding: 0.625rem 1.25rem;
  background: #fff;
  border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
  position: sticky;
  top: 0;
  z-index: 10;
}

.app-logo {
  font-size: 1.4rem;
  line-height: 1;
  flex-shrink: 0;
}

.app-header h1 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.01em;
  white-space: nowrap;
}

.app-tagline {
  font-size: 0.78rem;
  color: var(--text-muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* 3-column layout for lesson select */
.lesson-layout {
  display: grid;
  grid-template-columns: 240px 1fr 240px;
  flex: 1;
  align-items: start;
  min-height: 0;
}

.lesson-select-content {
  flex: 1;
  overflow-y: auto;
  padding: 1.5rem 1rem;
}

.lesson-groups {
  display: flex;
  flex-direction: column;
  gap: 2rem;
  max-width: 860px;
  margin: 0 auto;
  padding-bottom: 2rem;
}

/* Ad slots — shared between lesson-select and typing screens */
.ad-slot {
  padding: 1rem 0.625rem;
  position: sticky;
  top: 53px; /* below compact navbar */
  display: flex;
  justify-content: center;
}

.ad-placeholder {
  background: #fff;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  color: var(--text-muted);
}

/* Standard Google Wide Skyscraper: 160×600 */
.ad-skyscraper {
  width: 240px;
  height: calc(100vh - 106px);
}

.ad-label {
  font-size: 0.65rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  background: var(--bg-input);
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
}

/* Difficulty section header */
.difficulty-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 1.25rem;
  border-radius: var(--radius-md);
  margin-bottom: 1rem;
  gap: 1rem;
}

.diff-beginner     { background: #eff6ff; border: 1.5px solid #bfdbfe; }
.diff-intermediate { background: #fefce8; border: 1.5px solid #fde68a; }
.diff-advanced     { background: #fdf4ff; border: 1.5px solid #e9d5ff; }

.difficulty-header-left {
  display: flex;
  align-items: center;
  gap: 0.875rem;
}

.difficulty-icon {
  font-size: 1.75rem;
  line-height: 1;
}

.difficulty-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
}

.difficulty-desc {
  font-size: 0.78rem;
  color: var(--text-secondary);
  margin-top: 0.1rem;
}

.difficulty-progress {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 0.375rem;
  min-width: 80px;
}

.difficulty-count {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.difficulty-progress-bar {
  width: 80px;
  height: 5px;
  background: rgba(0,0,0,.08);
  border-radius: 99px;
  overflow: hidden;
}

.difficulty-progress-fill {
  height: 100%;
  background: var(--brand);
  border-radius: 99px;
  transition: width 0.4s ease;
}

/* Lesson grid */
.lesson-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(min(240px, 100%), 1fr));
  gap: 0.75rem;
  list-style: none;
}

/* Lesson card */
.lesson-card {
  background: #fff;
  border: 1.5px solid var(--border);
  border-radius: var(--radius-md);
  padding: 1rem;
  cursor: pointer;
  text-align: left;
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: 0.625rem;
  transition: border-color 0.15s, box-shadow 0.15s, transform 0.12s;
  box-shadow: var(--shadow-sm);
  position: relative;
}

.lesson-card:hover {
  border-color: var(--brand);
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.lesson-card:focus-visible {
  outline: 2px solid var(--brand);
  outline-offset: 2px;
  border-color: var(--brand);
}

.lesson-card.completed {
  border-color: #86efac;
  background: linear-gradient(135deg, #fff 60%, #f0fdf4 100%);
}

/* Lesson number badge */
.lesson-num {
  position: absolute;
  top: 0.75rem;
  right: 0.875rem;
  width: 1.5rem;
  height: 1.5rem;
  background: var(--bg-input);
  color: var(--text-muted);
  border-radius: 50%;
  font-size: 0.7rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
}

.lesson-card.completed .lesson-num {
  background: #dcfce7;
  color: #16a34a;
}

/* Card body */
.lesson-card-body {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
  padding-right: 1.75rem; /* avoid overlap with num badge */
}

.lesson-card-title-row {
  display: flex;
  align-items: center;
  gap: 0.375rem;
}

.lesson-card-title {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.3;
}

.lesson-card-preview {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  line-height: 1.4;
}

/* Card footer */
.lesson-card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: auto;
  padding-top: 0.5rem;
  border-top: 1px solid var(--border);
}

.lesson-card-pb {
  font-size: 0.78rem;
  color: #16a34a;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.lesson-card-pb::before {
  content: '⚡';
  font-size: 0.7rem;
}

.lesson-card-new {
  font-size: 0.75rem;
  color: var(--text-muted);
}

.lesson-card-arrow {
  font-size: 0.85rem;
  color: var(--text-muted);
  transition: transform 0.15s, color 0.15s;
}

.lesson-card:hover .lesson-card-arrow {
  transform: translateX(3px);
  color: var(--brand);
}

.completed-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: #16a34a;
  color: #fff;
  font-size: 0.6rem;
  width: 1rem;
  height: 1rem;
  border-radius: 50%;
  flex-shrink: 0;
}

/* ============================================================
   Typing Screen — top navbar
   ============================================================ */
.typing-navbar {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.625rem 1.25rem;
  background: #fff;
  border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
  position: sticky;
  top: 0;
  z-index: 10;
}

.typing-lesson-title {
  flex: 1;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  text-align: center;
}

/* ============================================================
   Typing Screen — 3-column layout
   ============================================================ */
.typing-layout {
  display: grid;
  grid-template-columns: 240px 1fr 240px;
  gap: 0;
  flex: 1;
  min-height: 0;
  align-items: start;
}

/* Ad slots */
.ad-slot {
  padding: 1rem 0.625rem;
  position: sticky;
  top: 53px;
}

.typing-layout .ad-slot {
  top: 53px;
}

/* Main content column */
.typing-main {
  padding: 1.5rem 1.25rem 2rem;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  min-width: 0;
}

/* ============================================================
   Stats bar
   ============================================================ */
.stats-bar {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0;
  background: #fff;
  border: 1.5px solid var(--border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
  width: fit-content;
  margin: 0 auto;
}

.stat-chip {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 0.625rem 1.5rem;
  min-width: 90px;
}

.stat-value {
  font-size: 1.375rem;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  color: var(--text-primary);
  line-height: 1.2;
  font-family: var(--font-mono);
}

.stat-label {
  font-size: 0.65rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  margin-top: 0.125rem;
}

.stat-divider {
  width: 1px;
  height: 2.5rem;
  background: var(--border);
  flex-shrink: 0;
}

/* ============================================================
   Passage card
   ============================================================ */
.passage-card {
  background: #fff;
  border: 1.5px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  padding: 1.75rem 2rem;
  position: relative;
  overflow: hidden;
}

/* Subtle top accent line */
.passage-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: linear-gradient(90deg, #3b82f6, #8b5cf6, #ec4899);
  border-radius: var(--radius-lg) var(--radius-lg) 0 0;
}

.passage-container {
  font-family: var(--font-mono);
  font-size: var(--passage-font-size);
  line-height: 2.2;
  letter-spacing: 0.03em;
  word-break: break-word;
  min-height: 5rem;
  color: var(--text-primary);
}

/* Character state classes */
.neutral   { color: var(--color-neutral); }
.correct   { color: var(--color-correct); }

.incorrect {
  color: var(--color-incorrect);
  background: #fee2e2; /* red-100 */
  border-radius: 2px;
}

.cursor {
  background: var(--color-cursor-bg);
  color: var(--color-cursor-fg);
  border-radius: 3px;
  padding: 0 1px;
  animation: blink-cursor 1s step-end infinite;
}

.incorrect.cursor {
  background: var(--color-incorrect);
  color: #fff;
  animation: none;
}

@keyframes blink-cursor {
  0%, 100% { opacity: 1; }
  50%       { opacity: 0.4; }
}

/* ============================================================
   Input field
   ============================================================ */
.input-wrapper {
  position: relative;
  display: flex;
  align-items: center;
}

.input-icon {
  position: absolute;
  left: 1rem;
  pointer-events: none;
  display: flex;
  align-items: center;
}

.typing-input {
  width: 100%;
  padding: 0.875rem 1rem 0.875rem 2.75rem;
  font-size: 1rem;
  font-family: var(--font-mono);
  background: #fff;
  color: var(--text-primary);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-md);
  outline: none;
  box-shadow: var(--shadow-sm);
  transition: border-color 0.15s, box-shadow 0.15s;
  caret-color: var(--brand);
}

.typing-input::placeholder {
  color: var(--text-muted);
  font-family: var(--font-sans);
  font-size: 0.9rem;
}

.typing-input:focus {
  border-color: var(--brand);
  box-shadow: 0 0 0 3px rgba(59,130,246,.15), var(--shadow-sm);
}

.input-hint {
  position: absolute;
  right: 1rem;
  font-size: 0.75rem;
  color: var(--text-muted);
  pointer-events: none;
  transition: opacity 0.2s;
}

.typing-input:focus ~ .input-hint,
.typing-input:not(:placeholder-shown) ~ .input-hint {
  opacity: 0;
}

/* ============================================================
   Virtual Keyboard
   ============================================================ */
.keyboard-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.625rem;
  padding: 1rem;
  background: #fff;
  border: 1.5px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  overflow-x: auto;
  max-width: 100%;
}

.keyboard {
  display: flex;
  flex-direction: column;
  gap: 5px;
  user-select: none;
}

.keyboard-row {
  display: flex;
  gap: 5px;
  justify-content: center;
}

.key {
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 2.4rem;
  height: 2.4rem;
  border-radius: var(--radius-sm);
  font-size: 0.72rem;
  font-family: var(--font-sans);
  font-weight: 600;
  border: 1px solid rgba(0,0,0,.12);
  box-shadow: 0 2px 0 rgba(0,0,0,.12);
  transition: transform 0.06s, box-shadow 0.06s;
  color: #1e293b;
}

.key.key-wide   { min-width: 3.8rem; }
.key.key-wider  { min-width: 5rem; }
.key.key-widest { min-width: 10rem; }

.key.key-highlight {
  transform: translateY(-2px) scale(1.12);
  box-shadow: 0 0 0 2.5px #fff, 0 0 0 4.5px var(--brand), 0 4px 8px rgba(59,130,246,.3);
  z-index: 1;
  position: relative;
}

.finger-label {
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text-secondary);
  min-height: 1.4em;
  text-align: center;
  background: var(--bg-input);
  padding: 0.25rem 0.875rem;
  border-radius: 20px;
}

/* ============================================================
   Finger Color Classes
   ============================================================ */
.finger-left-pinky   { background-color: var(--color-left-pinky); }
.finger-left-ring    { background-color: var(--color-left-ring); }
.finger-left-middle  { background-color: var(--color-left-middle); }
.finger-left-index   { background-color: var(--color-left-index); }
.finger-right-index  { background-color: var(--color-right-index); }
.finger-right-middle { background-color: var(--color-right-middle); }
.finger-right-ring   { background-color: var(--color-right-ring); }
.finger-right-pinky  { background-color: var(--color-right-pinky); }
.finger-thumb        { background-color: var(--color-thumb); }

/* ============================================================
   Results Screen
   ============================================================ */
.results-header {
  text-align: center;
  padding: 2.5rem 1.5rem 1.5rem;
  background: #fff;
  border-bottom: 1px solid var(--border);
}

.results-trophy {
  font-size: 2.5rem;
  margin-bottom: 0.5rem;
}

.results-header h2 {
  font-size: 1.75rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.results-subtitle {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-top: 0.25rem;
}

.results-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.5rem;
  max-width: 560px;
  margin: 0 auto;
  width: 100%;
  padding: 2rem 1.5rem;
}

.results-stats,
.pb-stats {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.75rem;
  width: 100%;
}

.result-item {
  background: #fff;
  border: 1.5px solid var(--border);
  border-radius: var(--radius-md);
  padding: 1.125rem 1rem;
  text-align: center;
  box-shadow: var(--shadow-sm);
}

.result-label {
  display: block;
  font-size: 0.7rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: 0.375rem;
}

.result-value {
  display: block;
  font-size: 2rem;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  color: var(--text-primary);
  font-family: var(--font-mono);
}

.personal-best-comparison {
  width: 100%;
  background: #f0fdf4;
  border: 1.5px solid #bbf7d0;
  border-radius: var(--radius-md);
  padding: 1rem;
}

.personal-best-comparison h3 {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: #16a34a;
  margin-bottom: 0.75rem;
  text-align: center;
}

.personal-best-comparison .result-item {
  background: #fff;
  border-color: #bbf7d0;
}

.results-actions {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
  justify-content: center;
}

.all-complete-msg {
  font-size: 1rem;
  text-align: center;
  color: #16a34a;
  font-weight: 500;
}

/* ============================================================
   Footer (home page only)
   ============================================================ */
.app-footer {
  background: #fff;
  border-top: 1px solid var(--border);
  padding: 0.875rem 1.5rem;
  text-align: center;
}

.footer-copy {
  font-size: 0.78rem;
  color: var(--text-muted);
}

/* ============================================================
   Error Message
   ============================================================ */
.error-msg {
  position: fixed;
  bottom: 1.5rem;
  left: 50%;
  transform: translateX(-50%);
  background: #dc2626;
  color: #fff;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-md);
  font-size: 0.9rem;
  font-weight: 500;
  z-index: 100;
  max-width: 90vw;
  text-align: center;
  box-shadow: var(--shadow-lg);
}

/* ============================================================
   Responsive
   ============================================================ */

/* Hide ad columns below 1100px */
@media (max-width: 1099px) {
  .typing-layout {
    grid-template-columns: 1fr;
  }
  .lesson-layout {
    grid-template-columns: 1fr;
  }
  .ad-slot { display: none; }
}

/* Hide keyboard below 768px */
@media (max-width: 767px) {
  .keyboard-container { display: none; }

  .typing-main { padding: 1rem; gap: 1rem; }

  .passage-card { padding: 1.25rem 1rem; }
  .passage-container { font-size: 1.25rem; line-height: 2; }

  .stats-bar { width: 100%; }
  .stat-chip { padding: 0.5rem 0.75rem; min-width: 0; flex: 1; }
  .stat-value { font-size: 1.1rem; }

  .results-stats, .pb-stats { grid-template-columns: repeat(2, 1fr); }
  .result-value { font-size: 1.5rem; }
}

@media (max-width: 479px) {
  .app-header h1 { font-size: 1.5rem; }
  .lesson-list { grid-template-columns: 1fr; }

  .typing-navbar { padding: 0.5rem 0.75rem; }
  .typing-lesson-title { font-size: 0.85rem; }

  .results-actions { flex-direction: column; width: 100%; }
  .results-actions .btn { width: 100%; justify-content: center; }
}

@media (max-width: 359px) {
  .passage-container { font-size: 0.9rem; }
  .results-stats, .pb-stats { grid-template-columns: 1fr; }
  .result-value { font-size: 1.25rem; }
}

/* Wider keyboard keys on large screens */
@media (min-width: 1200px) {
  .key { min-width: 2.75rem; height: 2.75rem; font-size: 0.78rem; }
  .key.key-wide   { min-width: 4.5rem; }
  .key.key-wider  { min-width: 6rem; }
  .key.key-widest { min-width: 12rem; }
}

/* ============================================================
   Focus indicators (Req 7.3)
   ============================================================ */
:focus-visible { outline: 2px solid var(--brand); outline-offset: 2px; }
.btn:focus-visible { outline: 2px solid var(--brand); outline-offset: 2px; }
.lesson-card:focus-visible { outline: 2px solid var(--brand); outline-offset: 2px; border-color: var(--brand); }
.typing-input:focus-visible { outline: none; } /* handled by box-shadow above */