/* ============================================
   DailyFluent Design System
   Semantic Color System - Deep Teal Theme
   
   Primary Brand: Deep Teal (#0D9488 / #2DD4BF)
   Accent: Amber (#F59E0B)
   
   WCAG AA Compliant
   ============================================ */

/* ============================================
   LIGHT MODE (Default)
   ============================================ */
:root {
  /* ----------------------------------------
     Color Palette (Internal Reference Only)
     ---------------------------------------- */
  --_teal-50: #F0FDFA;
  --_teal-100: #CCFBF1;
  --_teal-200: #99F6E4;
  --_teal-300: #5EEAD4;
  --_teal-400: #2DD4BF;
  --_teal-500: #14B8A6;
  --_teal-600: #0D9488;
  --_teal-700: #0F766E;
  --_teal-800: #115E59;
  --_teal-900: #134E4A;
  --_teal-950: #042F2E;

  --_amber-50: #FFFBEB;
  --_amber-100: #FEF3C7;
  --_amber-200: #FDE68A;
  --_amber-300: #FCD34D;
  --_amber-400: #FBBF24;
  --_amber-500: #F59E0B;
  --_amber-600: #D97706;
  --_amber-700: #B45309;

  --_red-50: #FEF2F2;
  --_red-100: #FEE2E2;
  --_red-500: #EF4444;
  --_red-600: #DC2626;
  --_red-700: #B91C1C;

  --_green-50: #F0FDF4;
  --_green-100: #DCFCE7;
  --_green-500: #22C55E;
  --_green-600: #16A34A;
  --_green-700: #15803D;

  --_blue-50: #EFF6FF;
  --_blue-100: #DBEAFE;
  --_blue-500: #3B82F6;
  --_blue-600: #2563EB;

  /* ----------------------------------------
     SEMANTIC TOKENS - Background
     ---------------------------------------- */
  /* App backgrounds */
  --bg-app: #FFFFFF;
  --bg-app-subtle: var(--_teal-50);
  --bg-app-muted: #F8FAFC;

  /* Surface backgrounds (cards, modals, dropdowns) */
  --bg-surface: #FFFFFF;
  --bg-surface-raised: #FFFFFF;
  --bg-surface-overlay: rgba(255, 255, 255, 0.95);

  /* Interactive backgrounds */
  --bg-interactive: var(--_teal-50);
  --bg-interactive-hover: var(--_teal-100);
  --bg-interactive-active: var(--_teal-200);
  --bg-interactive-selected: var(--_teal-100);

  /* Inverted (for tooltips, badges on dark) */
  --bg-inverted: var(--_teal-900);
  --bg-inverted-subtle: var(--_teal-800);

  /* ----------------------------------------
     SEMANTIC TOKENS - Text
     ---------------------------------------- */
  /* Primary text - highest contrast, main content */
  --text-primary: #0F172A;

  /* Secondary text - labels, descriptions */
  --text-secondary: #475569;

  /* Tertiary text - placeholders, hints */
  --text-tertiary: #94A3B8;

  /* Disabled text */
  --text-disabled: #CBD5E1;

  /* Inverted text (on dark backgrounds) */
  --text-inverted: #FFFFFF;
  --text-inverted-secondary: rgba(255, 255, 255, 0.8);

  /* Link text */
  --text-link: var(--_teal-600);
  --text-link-hover: var(--_teal-700);
  --text-link-visited: var(--_teal-800);

  /* ----------------------------------------
     SEMANTIC TOKENS - Brand / Action
     ---------------------------------------- */
  /* Primary action (buttons, links, focus rings) */
  --action-primary: var(--_teal-600);
  --action-primary-hover: var(--_teal-700);
  --action-primary-active: var(--_teal-800);
  --action-primary-subtle: var(--_teal-50);
  --action-primary-subtle-hover: var(--_teal-100);

  /* Primary action text (on primary bg) */
  --action-primary-text: #FFFFFF;

  /* Secondary action (outline buttons) */
  --action-secondary: var(--_teal-600);
  --action-secondary-hover: var(--_teal-700);
  --action-secondary-bg-hover: var(--_teal-50);

  /* Accent (streak, rewards, highlights) */
  --action-accent: var(--_amber-500);
  --action-accent-hover: var(--_amber-600);
  --action-accent-subtle: var(--_amber-50);
  --action-accent-text: #FFFFFF;

  /* ----------------------------------------
     SEMANTIC TOKENS - Status / Feedback
     ---------------------------------------- */
  /* Success */
  --status-success: var(--_green-600);
  --status-success-subtle: var(--_green-50);
  --status-success-text: var(--_green-700);
  --status-success-border: var(--_green-500);

  /* Warning */
  --status-warning: var(--_amber-500);
  --status-warning-subtle: var(--_amber-50);
  --status-warning-text: var(--_amber-700);
  --status-warning-border: var(--_amber-400);

  /* Error / Danger */
  --status-error: var(--_red-600);
  --status-error-subtle: var(--_red-50);
  --status-error-text: var(--_red-700);
  --status-error-border: var(--_red-500);

  /* Info */
  --status-info: var(--_blue-600);
  --status-info-subtle: var(--_blue-50);
  --status-info-text: var(--_blue-600);
  --status-info-border: var(--_blue-500);

  /* ----------------------------------------
     SEMANTIC TOKENS - Border
     ---------------------------------------- */
  --border-default: #E2E8F0;
  --border-subtle: #F1F5F9;
  --border-strong: #CBD5E1;
  --border-interactive: var(--_teal-300);
  --border-focus: var(--_teal-500);
  --border-error: var(--_red-500);
  --border-success: var(--_green-500);

  /* ----------------------------------------
     SEMANTIC TOKENS - Shadow
     ---------------------------------------- */
  --shadow-xs: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px -1px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);

  /* Colored shadows for depth */
  --shadow-primary: 0 4px 14px 0 rgba(13, 148, 136, 0.25);
  --shadow-accent: 0 4px 14px 0 rgba(245, 158, 11, 0.25);

  /* ----------------------------------------
     SEMANTIC TOKENS - Focus Ring
     ---------------------------------------- */
  --focus-ring: 0 0 0 2px var(--bg-surface), 0 0 0 4px var(--action-primary);
  --focus-ring-error: 0 0 0 2px var(--bg-surface), 0 0 0 4px var(--status-error);

  /* ----------------------------------------
     SEMANTIC TOKENS - Overlay
     ---------------------------------------- */
  --overlay-backdrop: rgba(15, 23, 42, 0.5);
  --overlay-subtle: rgba(15, 23, 42, 0.05);

  /* ----------------------------------------
     SEMANTIC TOKENS - Skeleton / Loading
     ---------------------------------------- */
  --skeleton-base: #E2E8F0;
  --skeleton-shine: #F1F5F9;

  /* ----------------------------------------
     SEMANTIC TOKENS - Gamification
     ---------------------------------------- */
  /* Streak fire */
  --streak-flame: var(--_amber-500);
  --streak-flame-glow: rgba(245, 158, 11, 0.3);

  /* XP / Points */
  --xp-color: var(--_teal-500);
  --xp-bg: var(--_teal-50);

  /* Coins / Currency */
  --coin-color: var(--_amber-500);
  --coin-bg: var(--_amber-50);

  /* Progress bars */
  --progress-track: var(--_teal-100);
  --progress-fill: var(--_teal-500);
  --progress-fill-success: var(--_green-500);

  /* Badges / Achievements */
  --badge-bronze: #CD7F32;
  --badge-silver: #C0C0C0;
  --badge-gold: #FFD700;
  --badge-platinum: #E5E4E2;

  /* ----------------------------------------
     SEMANTIC TOKENS - Learning States
     ---------------------------------------- */
  /* Correct answer */
  --answer-correct: var(--_green-500);
  --answer-correct-bg: var(--_green-50);
  --answer-correct-border: var(--_green-300);

  /* Wrong answer */
  --answer-wrong: var(--_red-500);
  --answer-wrong-bg: var(--_red-50);
  --answer-wrong-border: var(--_red-300);

  /* Selected (neutral) */
  --answer-selected: var(--_teal-500);
  --answer-selected-bg: var(--_teal-50);
  --answer-selected-border: var(--_teal-300);

  /* Highlight (text selection for study) */
  --highlight-yellow: rgba(250, 204, 21, 0.4);
  --highlight-green: rgba(74, 222, 128, 0.4);
  --highlight-blue: rgba(96, 165, 250, 0.4);
  --highlight-pink: rgba(244, 114, 182, 0.4);
  --highlight-purple: rgba(192, 132, 252, 0.4);

  /* ----------------------------------------
     Component Specific
     ---------------------------------------- */
  /* Sidebar */
  --sidebar-bg: #FFFFFF;
  --sidebar-border: var(--border-default);
  --sidebar-item-hover: var(--_teal-50);
  --sidebar-item-active: var(--_teal-100);
  --sidebar-item-active-border: var(--_teal-500);
  --sidebar-text: var(--text-secondary);
  --sidebar-text-active: var(--_teal-700);

  /* Topbar */
  --topbar-bg: #FFFFFF;
  --topbar-border: var(--border-default);

  /* Cards */
  --card-bg: #FFFFFF;
  --card-border: var(--border-default);
  --card-hover-border: var(--_teal-200);
  --card-shadow: var(--shadow-sm);
  --card-shadow-hover: var(--shadow-md);

  /* Input fields */
  --input-bg: #FFFFFF;
  --input-border: var(--border-default);
  --input-border-hover: var(--border-strong);
  --input-border-focus: var(--action-primary);
  --input-placeholder: var(--text-tertiary);

  /* Buttons */
  --btn-primary-bg: var(--action-primary);
  --btn-primary-bg-hover: var(--action-primary-hover);
  --btn-primary-text: var(--action-primary-text);
  --btn-secondary-bg: transparent;
  --btn-secondary-border: var(--action-secondary);
  --btn-secondary-text: var(--action-secondary);
  --btn-ghost-bg-hover: var(--bg-interactive-hover);

  /* Countdown timer */
  --countdown-bg: linear-gradient(135deg, #334155, #475569);
  --countdown-segment-bg: #1e293b;
  --countdown-text: #FFFFFF;
  --countdown-accent: #60A5FA;
  --countdown-label-text: rgba(255, 255, 255, 0.9);
  --countdown-unit-text: rgba(255, 255, 255, 0.65);
  --countdown-sep-color: rgba(255, 255, 255, 0.4);
  --countdown-divider: rgba(255, 255, 255, 0.2);
  --countdown-border: rgba(255, 255, 255, 0.1);
}


/* ============================================
   DARK MODE
   Using [data-theme='dark'] selector
   ============================================ */
[data-theme='dark'],
.dark {
  /* ----------------------------------------
     Color Palette Overrides
     ---------------------------------------- */
  --_teal-adjusted-400: #5EEAD4;
  /* Slightly desaturated for dark mode */
  --_teal-adjusted-500: #2DD4BF;

  /* ----------------------------------------
     SEMANTIC TOKENS - Background
     ---------------------------------------- */
  /* App backgrounds - using charcoal, not pure black */
  --bg-app: #0F172A;
  --bg-app-subtle: #1E293B;
  --bg-app-muted: #1E293B;

  /* Surface backgrounds */
  --bg-surface: #1E293B;
  --bg-surface-raised: #334155;
  --bg-surface-overlay: rgba(30, 41, 59, 0.95);

  /* Interactive backgrounds */
  --bg-interactive: rgba(45, 212, 191, 0.1);
  --bg-interactive-hover: rgba(45, 212, 191, 0.15);
  --bg-interactive-active: rgba(45, 212, 191, 0.2);
  --bg-interactive-selected: rgba(45, 212, 191, 0.15);

  /* Inverted */
  --bg-inverted: var(--_teal-100);
  --bg-inverted-subtle: var(--_teal-200);

  /* ----------------------------------------
     SEMANTIC TOKENS - Text
     ---------------------------------------- */
  --text-primary: #F1F5F9;
  --text-secondary: #94A3B8;
  --text-tertiary: #64748B;
  --text-disabled: #475569;
  --text-inverted: #0F172A;
  --text-inverted-secondary: rgba(15, 23, 42, 0.8);

  /* Links - brighter in dark mode */
  --text-link: var(--_teal-adjusted-400);
  --text-link-hover: var(--_teal-300);
  --text-link-visited: var(--_teal-adjusted-500);

  /* ----------------------------------------
     SEMANTIC TOKENS - Brand / Action
     ---------------------------------------- */
  /* Primary action - brighter for dark mode contrast */
  --action-primary: var(--_teal-adjusted-500);
  --action-primary-hover: var(--_teal-adjusted-400);
  --action-primary-active: var(--_teal-300);
  --action-primary-subtle: rgba(45, 212, 191, 0.15);
  --action-primary-subtle-hover: rgba(45, 212, 191, 0.25);
  --action-primary-text: #0F172A;

  /* Secondary action */
  --action-secondary: var(--_teal-adjusted-500);
  --action-secondary-hover: var(--_teal-adjusted-400);
  --action-secondary-bg-hover: rgba(45, 212, 191, 0.1);

  /* Accent - slightly brighter */
  --action-accent: #FBBF24;
  --action-accent-hover: #FCD34D;
  --action-accent-subtle: rgba(251, 191, 36, 0.15);
  --action-accent-text: #0F172A;

  /* ----------------------------------------
     SEMANTIC TOKENS - Status / Feedback
     (Desaturated/brightened for dark mode)
     ---------------------------------------- */
  /* Success */
  --status-success: #4ADE80;
  --status-success-subtle: rgba(74, 222, 128, 0.15);
  --status-success-text: #4ADE80;
  --status-success-border: #22C55E;

  /* Warning */
  --status-warning: #FBBF24;
  --status-warning-subtle: rgba(251, 191, 36, 0.15);
  --status-warning-text: #FBBF24;
  --status-warning-border: #F59E0B;

  /* Error */
  --status-error: #F87171;
  --status-error-subtle: rgba(248, 113, 113, 0.15);
  --status-error-text: #F87171;
  --status-error-border: #EF4444;

  /* Info */
  --status-info: #60A5FA;
  --status-info-subtle: rgba(96, 165, 250, 0.15);
  --status-info-text: #60A5FA;
  --status-info-border: #3B82F6;

  /* ----------------------------------------
     SEMANTIC TOKENS - Border
     ---------------------------------------- */
  --border-default: #334155;
  --border-subtle: #1E293B;
  --border-strong: #475569;
  --border-interactive: var(--_teal-adjusted-500);
  --border-focus: var(--_teal-adjusted-500);
  --border-error: #F87171;
  --border-success: #4ADE80;

  /* ----------------------------------------
     SEMANTIC TOKENS - Shadow
     (More subtle in dark mode)
     ---------------------------------------- */
  --shadow-xs: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
  --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.4), 0 1px 2px -1px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -2px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -4px rgba(0, 0, 0, 0.3);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.5), 0 8px 10px -6px rgba(0, 0, 0, 0.4);

  /* Colored shadows - more subtle glow effect */
  --shadow-primary: 0 4px 20px 0 rgba(45, 212, 191, 0.2);
  --shadow-accent: 0 4px 20px 0 rgba(251, 191, 36, 0.2);

  /* ----------------------------------------
     SEMANTIC TOKENS - Focus Ring
     ---------------------------------------- */
  --focus-ring: 0 0 0 2px var(--bg-surface), 0 0 0 4px var(--action-primary);
  --focus-ring-error: 0 0 0 2px var(--bg-surface), 0 0 0 4px var(--status-error);

  /* ----------------------------------------
     SEMANTIC TOKENS - Overlay
     ---------------------------------------- */
  --overlay-backdrop: rgba(0, 0, 0, 0.7);
  --overlay-subtle: rgba(0, 0, 0, 0.3);

  /* ----------------------------------------
     SEMANTIC TOKENS - Skeleton / Loading
     ---------------------------------------- */
  --skeleton-base: #334155;
  --skeleton-shine: #475569;

  /* ----------------------------------------
     SEMANTIC TOKENS - Gamification
     ---------------------------------------- */
  --streak-flame: #FBBF24;
  --streak-flame-glow: rgba(251, 191, 36, 0.4);

  --xp-color: var(--_teal-adjusted-400);
  --xp-bg: rgba(45, 212, 191, 0.15);

  --coin-color: #FBBF24;
  --coin-bg: rgba(251, 191, 36, 0.15);

  --progress-track: rgba(45, 212, 191, 0.2);
  --progress-fill: var(--_teal-adjusted-500);
  --progress-fill-success: #4ADE80;

  /* ----------------------------------------
     SEMANTIC TOKENS - Learning States
     ---------------------------------------- */
  --answer-correct: #4ADE80;
  --answer-correct-bg: rgba(74, 222, 128, 0.15);
  --answer-correct-border: rgba(74, 222, 128, 0.5);

  --answer-wrong: #F87171;
  --answer-wrong-bg: rgba(248, 113, 113, 0.15);
  --answer-wrong-border: rgba(248, 113, 113, 0.5);

  --answer-selected: var(--_teal-adjusted-500);
  --answer-selected-bg: rgba(45, 212, 191, 0.15);
  --answer-selected-border: rgba(45, 212, 191, 0.5);

  /* Highlights - slightly more opaque for dark bg */
  --highlight-yellow: rgba(250, 204, 21, 0.35);
  --highlight-green: rgba(74, 222, 128, 0.35);
  --highlight-blue: rgba(96, 165, 250, 0.35);
  --highlight-pink: rgba(244, 114, 182, 0.35);
  --highlight-purple: rgba(192, 132, 252, 0.35);

  /* ----------------------------------------
     Component Specific Overrides
     ---------------------------------------- */
  /* Sidebar */
  --sidebar-bg: #1E293B;
  --sidebar-border: #334155;
  --sidebar-item-hover: rgba(45, 212, 191, 0.1);
  --sidebar-item-active: rgba(45, 212, 191, 0.15);
  --sidebar-item-active-border: var(--_teal-adjusted-500);
  --sidebar-text: #94A3B8;
  --sidebar-text-active: var(--_teal-adjusted-400);

  /* Topbar */
  --topbar-bg: #1E293B;
  --topbar-border: #334155;

  /* Cards */
  --card-bg: #1E293B;
  --card-border: #334155;
  --card-hover-border: var(--_teal-700);
  --card-shadow: var(--shadow-sm);
  --card-shadow-hover: var(--shadow-md);

  /* Input fields */
  --input-bg: #0F172A;
  --input-border: #334155;
  --input-border-hover: #475569;
  --input-border-focus: var(--_teal-adjusted-500);
  --input-placeholder: #64748B;

  /* Buttons */
  --btn-primary-bg: var(--action-primary);
  --btn-primary-bg-hover: var(--action-primary-hover);
  --btn-primary-text: var(--action-primary-text);
  --btn-secondary-bg: transparent;
  --btn-secondary-border: var(--action-secondary);
  --btn-secondary-text: var(--action-secondary);
  --btn-ghost-bg-hover: var(--bg-interactive-hover);

  /* Countdown */
  --countdown-bg: linear-gradient(135deg, #0F172A, #1E293B);
  --countdown-segment-bg: #334155;
  --countdown-text: #F1F5F9;
  --countdown-accent: #2DD4BF;
  --countdown-label-text: rgba(241, 245, 249, 0.9);
  --countdown-unit-text: rgba(241, 245, 249, 0.6);
  --countdown-sep-color: rgba(241, 245, 249, 0.35);
  --countdown-divider: rgba(241, 245, 249, 0.15);
  --countdown-border: rgba(45, 212, 191, 0.2);
}


/* ============================================
   UTILITY CLASSES
   ============================================ */

/* Background utilities */
.bg-app {
  background-color: var(--bg-app);
}

.bg-app-subtle {
  background-color: var(--bg-app-subtle);
}

.bg-surface {
  background-color: var(--bg-surface);
}

.bg-surface-raised {
  background-color: var(--bg-surface-raised);
}

.bg-interactive {
  background-color: var(--bg-interactive);
}

.bg-primary {
  background-color: var(--action-primary);
}

.bg-accent {
  background-color: var(--action-accent);
}

/* Text utilities */
.text-primary {
  color: var(--text-primary);
}

.text-secondary {
  color: var(--text-secondary);
}

.text-tertiary {
  color: var(--text-tertiary);
}

.text-disabled {
  color: var(--text-disabled);
}

.text-inverted {
  color: var(--text-inverted);
}

.text-link {
  color: var(--text-link);
}

.text-action {
  color: var(--action-primary);
}

.text-accent {
  color: var(--action-accent);
}

/* Status utilities */
.text-success {
  color: var(--status-success-text);
}

.text-warning {
  color: var(--status-warning-text);
}

.text-error {
  color: var(--status-error-text);
}

.text-info {
  color: var(--status-info-text);
}

.bg-success {
  background-color: var(--status-success-subtle);
}

.bg-warning {
  background-color: var(--status-warning-subtle);
}

.bg-error {
  background-color: var(--status-error-subtle);
}

.bg-info {
  background-color: var(--status-info-subtle);
}

/* Border utilities */
.border-default {
  border-color: var(--border-default);
}

.border-subtle {
  border-color: var(--border-subtle);
}

.border-strong {
  border-color: var(--border-strong);
}

.border-primary {
  border-color: var(--action-primary);
}

.border-error {
  border-color: var(--border-error);
}

.border-success {
  border-color: var(--border-success);
}

/* Shadow utilities */
.shadow-xs {
  box-shadow: var(--shadow-xs);
}

.shadow-sm {
  box-shadow: var(--shadow-sm);
}

.shadow-md {
  box-shadow: var(--shadow-md);
}

.shadow-lg {
  box-shadow: var(--shadow-lg);
}

.shadow-xl {
  box-shadow: var(--shadow-xl);
}

.shadow-primary {
  box-shadow: var(--shadow-primary);
}

.shadow-accent {
  box-shadow: var(--shadow-accent);
}

/* Focus ring */
.focus-ring:focus {
  outline: none;
  box-shadow: var(--focus-ring);
}

.focus-ring-error:focus {
  outline: none;
  box-shadow: var(--focus-ring-error);
}


/* ============================================
   BASE ELEMENT STYLES
   ============================================ */

/* Apply theme to body */
body {
  background-color: var(--bg-app);
  color: var(--text-primary);
  transition: background-color 0.3s ease, color 0.3s ease;
}

/* Links */
a {
  color: var(--text-link);
  transition: color 0.15s ease;
}

a:hover {
  color: var(--text-link-hover);
}

/* Selection */
::selection {
  background-color: var(--action-primary);
  color: var(--action-primary-text);
}

/* Scrollbar styling */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-track {
  background: var(--bg-app-subtle);
}

::-webkit-scrollbar-thumb {
  background: var(--border-strong);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--text-tertiary);
}

/* Firefox scrollbar */
* {
  scrollbar-width: thin;
  scrollbar-color: var(--border-strong) var(--bg-app-subtle);
}


/* ============================================
   COMPONENT EXAMPLES
   ============================================ */

/* Primary Button */
.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.625rem 1.25rem;
  font-weight: 600;
  font-size: 0.875rem;
  border-radius: 0.5rem;
  background-color: var(--btn-primary-bg);
  color: var(--btn-primary-text);
  border: none;
  cursor: pointer;
  transition: all 0.15s ease;
  box-shadow: var(--shadow-sm);
}

.btn-primary:hover {
  background-color: var(--btn-primary-bg-hover);
  box-shadow: var(--shadow-primary);
  transform: translateY(-1px);
}

.btn-primary:active {
  transform: translateY(0);
}

.btn-primary:focus {
  outline: none;
  box-shadow: var(--focus-ring);
}

/* Secondary Button */
.btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.625rem 1.25rem;
  font-weight: 600;
  font-size: 0.875rem;
  border-radius: 0.5rem;
  background-color: var(--btn-secondary-bg);
  color: var(--btn-secondary-text);
  border: 2px solid var(--btn-secondary-border);
  cursor: pointer;
  transition: all 0.15s ease;
}

.btn-secondary:hover {
  background-color: var(--action-secondary-bg-hover);
}

.btn-secondary:focus {
  outline: none;
  box-shadow: var(--focus-ring);
}

/* Ghost Button */
.btn-ghost {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.625rem 1.25rem;
  font-weight: 500;
  font-size: 0.875rem;
  border-radius: 0.5rem;
  background-color: transparent;
  color: var(--text-secondary);
  border: none;
  cursor: pointer;
  transition: all 0.15s ease;
}

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

/* Card */
.card {
  background-color: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 0.75rem;
  padding: 1.25rem;
  box-shadow: var(--card-shadow);
  transition: all 0.2s ease;
}

.card:hover {
  border-color: var(--card-hover-border);
  box-shadow: var(--card-shadow-hover);
}

/* Input */
.input {
  width: 100%;
  padding: 0.625rem 0.875rem;
  font-size: 0.875rem;
  background-color: var(--input-bg);
  border: 1px solid var(--input-border);
  border-radius: 0.5rem;
  color: var(--text-primary);
  transition: all 0.15s ease;
}

.input::placeholder {
  color: var(--input-placeholder);
}

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

.input:focus {
  outline: none;
  border-color: var(--input-border-focus);
  box-shadow: var(--focus-ring);
}

.input.error {
  border-color: var(--border-error);
}

.input.error:focus {
  box-shadow: var(--focus-ring-error);
}

/* Badge */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 0.25rem 0.625rem;
  font-size: 0.75rem;
  font-weight: 600;
  border-radius: 9999px;
  background-color: var(--action-primary-subtle);
  color: var(--action-primary);
}

.badge-success {
  background-color: var(--status-success-subtle);
  color: var(--status-success-text);
}

.badge-warning {
  background-color: var(--status-warning-subtle);
  color: var(--status-warning-text);
}

.badge-error {
  background-color: var(--status-error-subtle);
  color: var(--status-error-text);
}

.badge-accent {
  background-color: var(--action-accent-subtle);
  color: var(--action-accent);
}

/* Progress bar */
.progress {
  width: 100%;
  height: 8px;
  background-color: var(--progress-track);
  border-radius: 9999px;
  overflow: hidden;
}

.progress-bar {
  height: 100%;
  background-color: var(--progress-fill);
  border-radius: 9999px;
  transition: width 0.3s ease;
}

.progress-bar.success {
  background-color: var(--progress-fill-success);
}

/* Streak flame icon */
.streak-icon {
  color: var(--streak-flame);
  filter: drop-shadow(0 0 8px var(--streak-flame-glow));
}

/* Coin icon */
.coin-icon {
  color: var(--coin-color);
  background-color: var(--coin-bg);
  border-radius: 50%;
  padding: 4px;
}

/* Answer states for quizzes */
.answer-option {
  padding: 0.875rem 1rem;
  border: 2px solid var(--border-default);
  border-radius: 0.75rem;
  background-color: var(--bg-surface);
  cursor: pointer;
  transition: all 0.15s ease;
}

.answer-option:hover {
  border-color: var(--border-interactive);
  background-color: var(--bg-interactive);
}

.answer-option.selected {
  border-color: var(--answer-selected-border);
  background-color: var(--answer-selected-bg);
}

.answer-option.correct {
  border-color: var(--answer-correct-border);
  background-color: var(--answer-correct-bg);
}

.answer-option.wrong {
  border-color: var(--answer-wrong-border);
  background-color: var(--answer-wrong-bg);
}

/* Alert / Toast */
.alert {
  padding: 1rem 1.25rem;
  border-radius: 0.5rem;
  border-left: 4px solid;
}

.alert-success {
  background-color: var(--status-success-subtle);
  border-color: var(--status-success-border);
  color: var(--status-success-text);
}

.alert-warning {
  background-color: var(--status-warning-subtle);
  border-color: var(--status-warning-border);
  color: var(--status-warning-text);
}

.alert-error {
  background-color: var(--status-error-subtle);
  border-color: var(--status-error-border);
  color: var(--status-error-text);
}

.alert-info {
  background-color: var(--status-info-subtle);
  border-color: var(--status-info-border);
  color: var(--status-info-text);
}

/* Skeleton loading */
.skeleton {
  background: linear-gradient(90deg,
      var(--skeleton-base) 25%,
      var(--skeleton-shine) 50%,
      var(--skeleton-base) 75%);
  background-size: 200% 100%;
  animation: skeleton-shimmer 1.5s infinite;
  border-radius: 0.25rem;
}

@keyframes skeleton-shimmer {
  0% {
    background-position: 200% 0;
  }

  100% {
    background-position: -200% 0;
  }
}

/* Text highlights for study mode */
.highlight-yellow {
  background-color: var(--highlight-yellow);
}

.highlight-green {
  background-color: var(--highlight-green);
}

.highlight-blue {
  background-color: var(--highlight-blue);
}

.highlight-pink {
  background-color: var(--highlight-pink);
}

.highlight-purple {
  background-color: var(--highlight-purple);
}