/* DiplomaStudy - CSS Variables v2 (Premium) */
:root {
  /* Brand Palette */
  --color-bg: #F7F5EF;
  --color-surface: #FFFFFF;
  --color-surface-hover: #F2F5F2;
  --color-surface-elevated: #FFFFFF;
  
  --color-forest: #1C3E2C;
  --color-forest-dark: #12291D;
  --color-forest-light: #285A3F;
  --color-forest-soft: rgba(28, 62, 44, 0.08);
  
  --color-sage: #7A9B7A;
  --color-sage-light: #E8EFE8;
  --color-sage-dark: #587858;
  
  --color-accent: #C87A1E;
  --color-accent-light: #FEF3C7;
  
  --color-text: #1C2720;
  --color-text-muted: #57675D;
  --color-text-dim: #84968B;
  --color-text-inverse: #FFFFFF;
  
  --color-border: #E1E8E1;
  --color-border-subtle: #EDF2ED;
  --color-divider: #E8EFE8;
  
  --color-success: #15803D;
  --color-success-bg: #DCFCE7;
  --color-warning: #B45309;
  --color-warning-bg: #FEF3C7;
  --color-danger: #B91C1C;
  --color-danger-bg: #FEE2E2;
  --color-info: #1D4ED8;
  --color-info-bg: #DBEAFE;

  /* ═══════════════════════════════════════════
     PREMIUM GRADIENT LIBRARY (NEW)
     ═══════════════════════════════════════════ */
  --grad-hero: linear-gradient(135deg, #1C3E2C 0%, #2A5540 50%, #1C3E2C 100%);
  --grad-forest: linear-gradient(135deg, #1C3E2C, #285A3F);
  --grad-sage: linear-gradient(135deg, #E8EFE8, #D5E3D5);
  --grad-accent: linear-gradient(135deg, #C87A1E, #E08E2B);
  --grad-warm: linear-gradient(135deg, #FEF3C7, #FDE68A);
  --grad-amber: linear-gradient(135deg, #F59E0B, #D97706);
  --grad-purple: linear-gradient(135deg, #7C3AED, #A78BFA);
  --grad-indigo: linear-gradient(135deg, #4338CA, #6366F1);
  --grad-cyan: linear-gradient(135deg, #0891B2, #22D3EE);
  --grad-rose: linear-gradient(135deg, #E11D48, #FB7185);

  /* ═══════════════════════════════════════════
     GLASS EFFECTS (NEW)
     ═══════════════════════════════════════════ */
  --glass-bg: rgba(255, 255, 255, 0.65);
  --glass-border: rgba(255, 255, 255, 0.3);
  --glass-blur: blur(20px) saturate(160%);
  --glass-shadow: 0 8px 32px rgba(28, 62, 44, 0.1);
  
  /* Typography Scale */
  --font-main: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Noto Sans Bengali", "Hind Siliguri", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.84375rem;
  --font-size-base: 0.9375rem;
  --font-size-md: 1.0625rem;
  --font-size-lg: 1.25rem;
  --font-size-xl: 1.5rem;
  --font-size-2xl: 1.875rem;
  
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.65;
  
  /* Radii */
  --radius-xs: 4px;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 20px;
  --radius-2xl: 24px;
  --radius-full: 9999px;
  
  /* ═══════════════════════════════════════════
     ELEVATION SYSTEM (Enhanced)
     ═══════════════════════════════════════════ */
  --shadow-xs: 0 1px 2px rgba(18, 41, 29, 0.04);
  --shadow-sm: 0 2px 4px rgba(18, 41, 29, 0.06), 0 1px 2px rgba(18, 41, 29, 0.04);
  --shadow-md: 0 4px 10px rgba(18, 41, 29, 0.07), 0 2px 4px rgba(18, 41, 29, 0.04);
  --shadow-lg: 0 10px 25px rgba(18, 41, 29, 0.1), 0 4px 10px rgba(18, 41, 29, 0.05);
  --shadow-xl: 0 20px 45px rgba(18, 41, 29, 0.15), 0 8px 20px rgba(18, 41, 29, 0.08);
  --shadow-glow: 0 8px 24px rgba(28, 62, 44, 0.18);
  
  /* Layout */
  --header-height: 56px;
  --bottom-nav-height: 64px;
  --max-content-width: 680px;
  --container-padding: 16px;
  
  /* ═══════════════════════════════════════════
     ANIMATION TIMING (Enhanced)
     ═══════════════════════════════════════════ */
  --transition-fast: 0.15s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-smooth: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-spring: 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
  --transition-bounce: 0.5s cubic-bezier(0.68, -0.55, 0.265, 1.55);
  
  --safe-bottom: env(safe-area-inset-bottom, 0px);
  --safe-top: env(safe-area-inset-top, 0px);
}

/* Dark Theme */
[data-theme="dark"] {
  --color-bg: #101712;
  --color-surface: #18231C;
  --color-surface-hover: #1F2E24;
  --color-surface-elevated: #202F26;
  
  --color-forest: #3F7557;
  --color-forest-dark: #274D38;
  --color-forest-light: #529470;
  --color-forest-soft: rgba(82, 148, 112, 0.15);
  
  --color-sage: #91B898;
  --color-sage-light: #1D2E22;
  --color-sage-dark: #B5D4BB;
  
  --color-accent: #E08E2B;
  --color-accent-light: #302410;
  
  --color-text: #EDF3EE;
  --color-text-muted: #97A89D;
  --color-text-dim: #6E7F73;
  --color-text-inverse: #101712;
  
  --color-border: #233429;
  --color-border-subtle: #1B2920;
  --color-divider: #233429;
  
  --color-success: #34D399;
  --color-success-bg: #064E3B;
  --color-warning: #FBBF24;
  --color-warning-bg: #451A03;
  --color-danger: #F87171;
  --color-danger-bg: #450A0A;
  --color-info: #60A5FA;
  --color-info-bg: #172554;
  
  /* Dark gradients */
  --grad-hero: linear-gradient(135deg, #12291D 0%, #1F3D2C 50%, #12291D 100%);
  --grad-forest: linear-gradient(135deg, #274D38, #3F7557);
  
  /* Glass for dark */
  --glass-bg: rgba(32, 47, 38, 0.65);
  --glass-border: rgba(255, 255, 255, 0.08);
  --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.5);
  
  /* Shadows for dark */
  --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.2);
  --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.25);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.35);
  --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.45);
  --shadow-xl: 0 20px 45px rgba(0, 0, 0, 0.55);
  --shadow-glow: 0 8px 24px rgba(82, 148, 112, 0.25);
}