/**
 * Parli – Global Design System
 * Single source of truth for every page and reusable component.
 *
 * Use semantic tokens (for example --surface-page or --text-primary)
 * in page styles. Palette tokens should only describe a color and make
 * future themes or brand updates possible without rewriting components.
 */

:root {
  /* ============================================================
     COLORS – Duolingo Brand Palette
     https://design.duolingo.com/identity/color
     ============================================================ */

  /* Core brand */
  --color-feather-green: #58CC02;
  --color-mask-green: #89E219;
  --color-tree-green: #58A700;
  --color-eel: #4B4B4B;
  --color-snow: #FFFFFF;

  /* Secondary accents (Macaw, Cardinal, Bee, Fox, Beetle, Humpback) */
  --color-macaw: #1CB0F6;
  --color-cardinal: #FF4B4B;
  --color-bee: #FFC800;
  --color-fox: #FF9600;
  --color-beetle: #CE82FF;
  --color-humpback: #2B70C9;

  /* Neutrals (Eel, Wolf, Hare, Swan, Polar, Snow) */
  --color-wolf: #777777;
  --color-hare: #AFAFAF;
  --color-swan: #E5E5E5;
  --color-polar: #F7F7F7;

  /* Primary: Feather Green */
  --color-primary: var(--color-feather-green);
  --color-primary-dark: var(--color-tree-green);
  --color-primary-light: var(--color-mask-green);
  --color-primary-xlight: #D7FFB8;
  --color-primary-shadow: var(--color-tree-green);
  --color-primary-rgb: 88, 204, 2;
  --color-primary-dark-rgb: 88, 167, 0;
  --color-primary-contrast: var(--color-snow);

  /* Secondary: Macaw Blue */
  --color-secondary: var(--color-macaw);
  --color-secondary-dark: #1899D6;
  --color-secondary-light: #44C0F8;
  --color-secondary-xlight: #DDF4FF;
  --color-secondary-shadow: #1899D6;
  --color-secondary-rgb: 28, 176, 246;
  --color-secondary-contrast: var(--color-snow);

  /* Success: Feather Green */
  --color-success: var(--color-feather-green);
  --color-success-dark: var(--color-tree-green);
  --color-success-light: var(--color-mask-green);
  --color-success-xlight: #D7FFB8;
  --color-success-soft: #A5ED6E;
  --color-success-shadow: var(--color-tree-green);
  --color-success-rgb: 88, 204, 2;
  --color-success-contrast: var(--color-snow);

  /* Warning: Bee Yellow */
  --color-warning: var(--color-bee);
  --color-warning-dark: #E5B200;
  --color-warning-light: #FFD433;
  --color-warning-xlight: #FFF8D6;
  --color-warning-shadow: #E5B200;
  --color-warning-rgb: 255, 200, 0;
  --color-warning-contrast: var(--color-eel);

  /* Error: Cardinal Red */
  --color-error: var(--color-cardinal);
  --color-error-dark: #EA2B2B;
  --color-error-light: #FF6E6E;
  --color-error-xlight: #FFDFDF;
  --color-error-shadow: #EA2B2B;
  --color-error-rgb: 255, 75, 75;
  --color-error-contrast: var(--color-snow);

  /* XP / League: Beetle Purple */
  --color-xp: var(--color-beetle);
  --color-xp-dark: #A559D6;
  --color-xp-light: #D99BFF;
  --color-xp-xlight: #F6E5FF;
  --color-xp-shadow: #A559D6;
  --color-xp-rgb: 206, 130, 255;
  --color-xp-contrast: var(--color-snow);

  /* Speaking: Humpback Blue */
  --color-speaking: var(--color-humpback);
  --color-speaking-dark: #2360B0;
  --color-speaking-light: #4A8AD4;
  --color-speaking-xlight: #E8F0FA;
  --color-speaking-shadow: #2360B0;
  --color-speaking-rgb: 43, 112, 201;
  --color-speaking-contrast: var(--color-snow);

  /* Streak: Fox Orange */
  --color-streak: var(--color-fox);
  --color-streak-dark: #E58700;
  --color-streak-light: #FFAA33;
  --color-streak-xlight: #FFF0D6;
  --color-streak-shadow: #E58700;
  --color-streak-soft: #FFD9C2;
  --color-streak-soft-border: #FFB366;
  --color-streak-rgb: 255, 150, 0;
  --color-streak-contrast: var(--color-snow);

  /* Lesson intro / teach cards */
  --color-teach: var(--color-beetle);
  --color-teach-dark: #A559D6;
  --color-teach-soft: #E8C9FF;
  --color-teach-rgb: 206, 130, 255;
  --color-combo-hot: #FF5200;
  --color-combo-hot-rgb: 255, 82, 0;
  --color-heart: var(--color-cardinal);
  --color-shadow-rgb: 0, 0, 0;

  /* Soft accent borders used for paths, quests and speaking cards */
  --color-primary-soft: #A5ED6E;
  --color-primary-soft-shadow: #86D94A;
  --color-secondary-soft: #B8E7FC;
  --color-speaking-soft: #B8D4F0;

  /* Pari mascot palette */
  --color-mascot-fur: #F58232;
  --color-mascot-fur-dark: #C94F13;
  --color-mascot-fur-dark-rgb: 201, 79, 19;
  --color-mascot-cream: #FFF1D6;
  --color-mascot-ear: #FFB28A;
  --color-mascot-eye: #4B2B20;
  --color-mascot-muzzle: #FFF8E9;
  --color-mascot-nose: #3C2A25;
  --color-mascot-smile: #713B29;
  --color-mascot-scarf: #224A82;
  --color-mascot-scarf-dark: #173964;

  /* ============================================================
     NEUTRALS & CARD BACKGROUNDS
     ============================================================ */
  --color-neutral-50: var(--color-snow);
  --color-neutral-100: var(--color-polar);
  --color-neutral-150: var(--color-swan);
  --color-neutral-200: #D0D0D0;
  --color-neutral-300: var(--color-hare);
  --color-neutral-400: var(--color-wolf);
  --color-neutral-500: var(--color-wolf);
  --color-neutral-600: var(--color-eel);
  --color-neutral-700: var(--color-eel);
  --color-neutral-800: #333333;
  --color-neutral-900: #1A1A1A;

  /* Semantic surfaces – use these in new page and component styles. */
  --surface-page: var(--color-neutral-50);
  --surface-default: var(--color-neutral-50);
  --surface-subtle: var(--color-neutral-100);
  --surface-raised: var(--color-neutral-100);
  --surface-sunken: var(--color-neutral-150);
  --surface-disabled: var(--color-neutral-150);
  --surface-overlay: rgba(32, 32, 32, 0.65);
  --surface-glass: rgba(255, 255, 255, 0.92);
  --surface-dark-track: rgba(0, 0, 0, 0.17);
  --surface-white-95: rgba(255, 255, 255, 0.95);
  --surface-white-94: rgba(255, 255, 255, 0.94);
  --surface-white-90: rgba(255, 255, 255, 0.90);
  --surface-white-75: rgba(255, 255, 255, 0.75);
  --surface-white-70: rgba(255, 255, 255, 0.70);
  --surface-white-60: rgba(255, 255, 255, 0.60);
  --surface-white-40: rgba(255, 255, 255, 0.40);
  --surface-white-30: rgba(255, 255, 255, 0.30);
  --surface-white-25: rgba(255, 255, 255, 0.25);
  --surface-white-20: rgba(255, 255, 255, 0.20);
  --surface-white-18: rgba(255, 255, 255, 0.18);

  /* Colored surfaces and borders derived from the palette */
  --surface-primary-subtle: rgba(var(--color-primary-rgb), 0.06);
  --surface-primary-muted: rgba(var(--color-primary-rgb), 0.10);
  --surface-secondary-subtle: rgba(var(--color-secondary-rgb), 0.10);
  --surface-success-calendar-1: rgba(var(--color-success-rgb), 0.30);
  --surface-success-calendar-2: rgba(var(--color-success-rgb), 0.55);
  --surface-streak-muted: rgba(var(--color-streak-rgb), 0.20);
  --surface-teach-subtle: rgba(var(--color-teach-rgb), 0.06);
  --surface-teach-muted: rgba(var(--color-teach-rgb), 0.10);
  --border-primary-subtle: rgba(var(--color-primary-rgb), 0.15);
  --border-primary-soft: rgba(var(--color-primary-rgb), 0.20);
  --border-teach-subtle: rgba(var(--color-teach-rgb), 0.15);

  /* Backwards-compatible names used throughout the existing app. */
  --bg-base: var(--surface-page);
  --bg-card: var(--surface-default);
  --bg-overlay: var(--surface-overlay);
  --bg-glass: var(--surface-glass);

  /* ============================================================
     TEXT
     ============================================================ */
  --text-primary: var(--color-eel);
  --text-secondary: var(--color-wolf);
  --text-tertiary: var(--color-hare);
  --text-disabled: var(--color-neutral-300);
  --text-link: var(--color-secondary-dark);
  --text-inverse: #FFFFFF;
  --text-on-primary: var(--color-primary-contrast);
  --text-on-secondary: var(--color-secondary-contrast);
  --text-on-success: var(--color-success-contrast);
  --text-on-warning: var(--color-warning-contrast);
  --text-on-error: var(--color-error-contrast);

  /* ============================================================
     BORDERS & RADIUS
     ============================================================ */
  --border-color: var(--color-swan);
  --border-color-strong: #D0D0D0;
  --border-light: var(--color-swan);
  --border-color-focus: var(--color-secondary);
  --border-color-disabled: var(--color-neutral-200);
  --border-width-thin: 1px;
  --border-width: 2px;
  --border-width-strong: 3px;
  
  --border-radius-xs: 8px;
  --border-radius-sm: 12px;
  --border-radius-md: 16px;
  --border-radius-lg: 20px;
  --border-radius-xl: 24px;
  --border-radius-2xl: 28px;
  --border-radius-full: 9999px;

  /* ============================================================
     COMPLETE CARD THEMES
     Background, border, text and shadow always travel together.
     Components should use these tokens instead of mixing palette values.
     ============================================================ */
  --card-neutral-background: var(--surface-default);
  --card-neutral-border: var(--border-color);
  --card-neutral-text: var(--text-primary);
  --card-neutral-shadow: var(--shadow-card-neutral);

  --card-primary-background: var(--color-primary-xlight);
  --card-primary-border: var(--color-primary-soft);
  --card-primary-text: var(--color-primary-dark);
  --card-primary-shadow: var(--shadow-card-primary);

  --card-secondary-background: var(--color-secondary-xlight);
  --card-secondary-border: var(--color-secondary-soft);
  --card-secondary-text: var(--color-secondary-dark);
  --card-secondary-shadow: var(--shadow-card-secondary);

  --card-success-background: var(--color-success-xlight);
  --card-success-border: var(--color-success-soft);
  --card-success-text: var(--color-success-dark);
  --card-success-shadow: var(--shadow-card-success);

  --card-warning-background: var(--color-warning-xlight);
  --card-warning-border: var(--color-warning-light);
  --card-warning-text: var(--color-warning-dark);
  --card-warning-shadow: var(--shadow-card-warning);

  --card-error-background: var(--color-error-xlight);
  --card-error-border: var(--color-error-light);
  --card-error-text: var(--color-error-dark);
  --card-error-shadow: var(--shadow-card-error);

  --card-xp-background: var(--color-xp-xlight);
  --card-xp-border: var(--color-xp-light);
  --card-xp-text: var(--color-xp-dark);
  --card-xp-shadow: var(--shadow-card-xp);

  --card-speaking-background: var(--color-speaking-xlight);
  --card-speaking-border: var(--color-speaking-soft);
  --card-speaking-text: var(--color-speaking-dark);
  --card-speaking-shadow: var(--shadow-card-speaking);

  --card-streak-background: var(--color-streak-xlight);
  --card-streak-border: var(--color-streak-soft);
  --card-streak-text: var(--color-streak-dark);
  --card-streak-shadow: var(--shadow-card-streak);

  --card-teach-background: var(--color-xp-xlight);
  --card-teach-border: var(--color-teach-soft);
  --card-teach-text: var(--color-teach-dark);
  --card-teach-shadow: var(--shadow-card-teach);

  --card-accent-background: var(--color-primary);
  --card-accent-border: var(--color-teach-soft);
  --card-accent-text: var(--text-inverse);
  --card-accent-shadow: var(--shadow-card-teach);

  /* ============================================================
     SHADOWS & 3D ELEVATION
     ============================================================ */
  --shadow-xs: 0 2px 4px rgba(0, 0, 0, 0.04);
  --shadow-sm: 0 4px 0 var(--color-swan);
  --shadow-md: 0 6px 0 var(--color-swan), 0 10px 20px rgba(0, 0, 0, 0.05);
  --shadow-lg: 0 8px 0 var(--color-swan), 0 16px 32px rgba(0, 0, 0, 0.08);
  --shadow-xl: 0 12px 32px rgba(0, 0, 0, 0.16);
  --shadow-overlay: 0 20px 48px rgba(0, 0, 0, 0.18);
  --shadow-focus: 0 0 0 4px rgba(var(--color-secondary-rgb), 0.22);
  --shadow-disabled: 0 4px 0 var(--color-neutral-200);
  /* Strong 3D button shadows */
  --shadow-button-neutral: 0 5px 0 var(--border-color);
  --shadow-button-primary: 0 5px 0 var(--color-primary-shadow);
  --shadow-button-secondary: 0 5px 0 var(--color-secondary-shadow);
  --shadow-button-success: 0 5px 0 var(--color-success-shadow);
  --shadow-button-warning: 0 5px 0 var(--color-warning-shadow);
  --shadow-button-error: 0 5px 0 var(--color-error-shadow);
  --shadow-button-xp: 0 5px 0 var(--color-xp-shadow);
  --shadow-button-speaking: 0 5px 0 var(--color-speaking-shadow);
  --shadow-button-streak: 0 5px 0 var(--color-streak-shadow);

  --shadow-button-neutral-pressed: 0 1px 0 var(--border-color);
  --shadow-button-primary-pressed: 0 1px 0 var(--color-primary-shadow);
  --shadow-button-secondary-pressed: 0 1px 0 var(--color-secondary-shadow);
  --shadow-button-success-pressed: 0 1px 0 var(--color-success-shadow);
  --shadow-button-warning-pressed: 0 1px 0 var(--color-warning-shadow);
  --shadow-button-error-pressed: 0 1px 0 var(--color-error-shadow);
  --shadow-button-xp-pressed: 0 1px 0 var(--color-xp-shadow);
  --shadow-button-speaking-pressed: 0 1px 0 var(--color-speaking-shadow);
  --shadow-button-streak-pressed: 0 1px 0 var(--color-streak-shadow);

  /* Backwards-compatible aliases */
  --shadow-3d-btn: var(--shadow-button-primary);
  --shadow-primary: var(--shadow-button-primary);
  --shadow-secondary: var(--shadow-button-secondary);

  /* Soft 3D card shadows – paired with each semantic color.
     Use the stronger --shadow-primary/secondary values for buttons. */
  --shadow-card-neutral: 0 4px 0 var(--border-color);
  --shadow-card-primary: 0 4px 0 var(--color-primary-soft);
  --shadow-card-secondary: 0 4px 0 var(--color-secondary-soft);
  --shadow-card-success: 0 4px 0 var(--color-success-soft);
  --shadow-card-warning: 0 4px 0 var(--color-warning-light);
  --shadow-card-error: 0 4px 0 var(--color-error-light);
  --shadow-card-xp: 0 4px 0 var(--color-xp-light);
  --shadow-card-speaking: 0 4px 0 var(--color-speaking-soft);
  --shadow-card-streak: 0 4px 0 var(--color-streak-soft);
  --shadow-card-teach: 0 4px 0 var(--color-teach-soft);

  /* Pressed variants keep the same color relationship. */
  --shadow-card-neutral-pressed: 0 1px 0 var(--border-color);
  --shadow-card-primary-pressed: 0 1px 0 var(--color-primary-soft);
  --shadow-card-secondary-pressed: 0 1px 0 var(--color-secondary-soft);
  --shadow-card-success-pressed: 0 1px 0 var(--color-success-soft);
  --shadow-card-warning-pressed: 0 1px 0 var(--color-warning-light);
  --shadow-card-error-pressed: 0 1px 0 var(--color-error-light);
  --shadow-card-xp-pressed: 0 1px 0 var(--color-xp-light);
  --shadow-card-speaking-pressed: 0 1px 0 var(--color-speaking-soft);
  --shadow-card-streak-pressed: 0 1px 0 var(--color-streak-soft);
  --shadow-card-teach-pressed: 0 1px 0 var(--color-teach-soft);

  --shadow-nav: 0 -6px 20px rgba(0, 0, 0, 0.04);
  --shadow-card-soft: 0 4px 12px rgba(0, 0, 0, 0.06);
  --shadow-inset-pressed: inset 0 2px 0 rgba(0, 0, 0, 0.08);
  --shadow-drop-md: 0 8px 24px rgba(0, 0, 0, 0.15);
  --shadow-drop-lg: 0 8px 24px rgba(0, 0, 0, 0.25);
  --filter-drop-md: drop-shadow(0 8px 24px rgba(var(--color-shadow-rgb), 0.15));
  --filter-drop-lg: drop-shadow(0 8px 24px rgba(var(--color-shadow-rgb), 0.25));
  --shadow-primary-glow-sm: 0 4px 10px rgba(var(--color-primary-rgb), 0.20);
  --shadow-primary-glow-md: 0 4px 12px rgba(var(--color-primary-rgb), 0.30);
  --shadow-secondary-glow: 0 8px 16px rgba(var(--color-secondary-rgb), 0.30);
  --shadow-success-glow: 0 4px 12px rgba(var(--color-success-rgb), 0.30);
  --shadow-error-glow: 0 4px 12px rgba(var(--color-error-rgb), 0.30);
  --shadow-speaking-glow: 0 6px 20px rgba(var(--color-speaking-rgb), 0.20);
  --shadow-streak-glow-sm: 0 4px 12px rgba(var(--color-streak-rgb), 0.30);
  --shadow-streak-glow-md: 0 4px 15px rgba(var(--color-streak-rgb), 0.40);
  --shadow-streak-glow-lg: 0 8px 25px rgba(var(--color-streak-rgb), 0.60);
  --shadow-xp-glow: 0 2px 8px rgba(var(--color-xp-rgb), 0.40);
  --shadow-xp-text: 0 2px 8px rgba(var(--color-xp-rgb), 0.50);
  --shadow-combo: 0 4px 15px rgba(var(--color-streak-rgb), 0.40);
  --shadow-combo-pop: 0 8px 25px rgba(var(--color-streak-rgb), 0.60);
  --shadow-feedback-correct-sm: 0 -5px 20px rgba(var(--color-primary-rgb), 0.20);
  --shadow-feedback-correct-lg: 0 -5px 30px rgba(var(--color-primary-rgb), 0.50);
  --shadow-reward-idle: 0 4px 15px rgba(var(--color-primary-rgb), 0.10);
  --shadow-reward-active: 0 8px 30px rgba(var(--color-primary-rgb), 0.45), 0 0 20px rgba(var(--color-warning-rgb), 0.30);

  /* Solid surfaces – legacy names kept so existing var(--gradient-*) references stay valid */
  --gradient-primary: var(--color-primary);
  --gradient-primary-soft: var(--color-primary-xlight);
  --gradient-primary-button: var(--color-primary);
  --gradient-secondary: var(--color-secondary);
  --gradient-speaking: var(--color-speaking);
  --gradient-streak: var(--color-streak);
  --gradient-combo: var(--color-streak);
  --gradient-accent: var(--color-primary);
  --gradient-levelup: var(--color-beetle);
  --gradient-onboarding: var(--color-polar);
  --gradient-streak-badge: var(--color-streak-xlight);

  /* ============================================================
     TYPOGRAPHY
     ============================================================ */
  --font-display: 'Nunito', system-ui, -apple-system, sans-serif;
  --font-body: 'Nunito', system-ui, -apple-system, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Consolas, 'Liberation Mono', monospace;

  --text-xs: 0.75rem;     /* 12px */
  --text-sm: 0.875rem;    /* 14px */
  --text-base: 1rem;      /* 16px */
  --text-md: 1.125rem;    /* 18px */
  --text-lg: 1.25rem;     /* 20px */
  --text-xl: 1.5rem;      /* 24px */
  --text-2xl: 1.875rem;   /* 30px */
  --text-3xl: 2.25rem;    /* 36px */
  --text-4xl: 3rem;       /* 48px */
  --text-page-title: clamp(1.75rem, 5vw, 2.25rem);
  --text-section-title: clamp(1.25rem, 3vw, 1.5rem);

  --weight-regular: 500;
  --weight-medium: 600;
  --weight-semibold: 700;
  --weight-bold: 800;
  --weight-extrabold: 850;
  --weight-black: 900;

  --line-tight: 1.2;
  --line-snug: 1.35;
  --line-base: 1.5;
  --line-relaxed: 1.7;

  --tracking-tight: -0.03em;
  --tracking-normal: 0;
  --tracking-wide: 0.06em;
  --tracking-caps: 0.09em;

  /* ============================================================
     SPACING & LAYOUT
     ============================================================ */
  --space-0: 0;
  --space-1: 0.25rem;   /* 4px */
  --space-2: 0.5rem;    /* 8px */
  --space-3: 0.75rem;   /* 12px */
  --space-4: 1rem;      /* 16px */
  --space-5: 1.25rem;   /* 20px */
  --space-6: 1.5rem;    /* 24px */
  --space-8: 2rem;      /* 32px */
  --space-10: 2.5rem;   /* 40px */
  --space-12: 3rem;     /* 48px */
  --space-16: 4rem;     /* 64px */

  --page-padding: clamp(16px, 4vw, 24px);
  --page-block-padding: clamp(20px, 5vw, 32px);
  --section-gap: var(--space-6);
  --content-gap: var(--space-4);

  --duration-fast: 120ms;
  --duration-base: 200ms;
  --duration-slow: 300ms;
  --duration-modal: 360ms;

  --ease-standard: cubic-bezier(0.2, 0, 0, 1);
  --ease-accelerate: cubic-bezier(0.4, 0, 1, 1);
  --ease-decelerate: cubic-bezier(0, 0, 0.2, 1);
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
  --ease-bounce: cubic-bezier(0.34, 1.8, 0.64, 1);

  /* Shared interactive states. */
  --opacity-muted: 0.72;
  --opacity-disabled: 0.5;
  --pressed-depth: translateY(3px);
  --pressed-scale: scale(0.96);
  --focus-ring: 0 0 0 4px rgba(var(--color-secondary-rgb), 0.22);

  --nav-height: 82px;
  --header-height: 64px;
  --content-max-width: 600px;
  --content-wide-max-width: 960px;
  --content-reading-max-width: 68ch;
  --touch-target-min: 48px;
  --control-height-sm: 40px;
  --control-height-md: 48px;
  --control-height-lg: 56px;
  --icon-size-sm: 18px;
  --icon-size-md: 24px;
  --icon-size-lg: 32px;

  /* Safe Area Variables for iOS Notch & Dynamic Island */
  --safe-area-top: env(safe-area-inset-top, 0px);
  --safe-area-bottom: env(safe-area-inset-bottom, 0px);
  --safe-area-left: env(safe-area-inset-left, 0px);
  --safe-area-right: env(safe-area-inset-right, 0px);

  --z-below: -1;
  --z-base: 0;
  --z-raised: 10;
  --z-overlay: 100;
  --z-modal: 200;
  --z-toast: 300;
  --z-confetti: 400;
  --z-loading: 500;
}