/* ============================================
   Acqua Design System - CSS Custom Properties
   ============================================ */

:root {
  /* === Colors === */
  --color-primary: #1A2B5F;
  --color-primary-light: #2E4A8A;
  --color-primary-dark: #0F1A3D;

  --color-accent-start: #2E7CF6;
  --color-accent-end: #00D4AA;
  --color-accent-gradient: linear-gradient(135deg, var(--color-accent-start), var(--color-accent-end));

  --color-bg-base: #FAFBFC;
  --color-bg-alt: #F0F2F5;
  --color-bg-white: #FFFFFF;
  --color-bg-dark: #0D1117;

  --color-text-primary: #1E1E2E;
  --color-text-secondary: #5A5E6B;
  --color-text-muted: #8B8FA3;
  --color-text-white: #FFFFFF;
  --color-text-accent: var(--color-accent-start);

  --color-border: #E2E5EB;
  --color-border-light: #F0F2F5;

  --color-success: #00D4AA;
  --color-warning: #FFB347;
  --color-danger: #FF6B6B;

  /* === Typography === */
  --font-family-ja: "Noto Sans JP", "Hiragino Kaku Gothic ProN", "Hiragino Sans", Meiryo, sans-serif;
  --font-family-en: "Inter", -apple-system, BlinkMacSystemFont, sans-serif;
  --font-family-base: var(--font-family-ja);

  --font-size-xs: 0.75rem;     /* 12px */
  --font-size-sm: 0.875rem;    /* 14px */
  --font-size-base: 1rem;      /* 16px */
  --font-size-md: 1.125rem;    /* 18px */
  --font-size-lg: 1.25rem;     /* 20px */
  --font-size-xl: 1.5rem;      /* 24px */
  --font-size-2xl: 2rem;       /* 32px */
  --font-size-3xl: 2.5rem;     /* 40px */
  --font-size-4xl: 3rem;       /* 48px */
  --font-size-5xl: 3.5rem;     /* 56px */
  --font-size-hero: clamp(2rem, 5vw, 3.5rem);
  --font-size-section-title: clamp(1.5rem, 3.5vw, 2.5rem);

  --font-weight-regular: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  --font-weight-black: 900;

  --line-height-tight: 1.3;
  --line-height-base: 1.8;
  --line-height-relaxed: 2.0;

  --letter-spacing-tight: -0.02em;
  --letter-spacing-base: 0.04em;
  --letter-spacing-wide: 0.08em;
  --letter-spacing-wider: 0.12em;

  /* === Spacing === */
  --space-xs: 0.25rem;    /* 4px */
  --space-sm: 0.5rem;     /* 8px */
  --space-md: 1rem;       /* 16px */
  --space-lg: 1.5rem;     /* 24px */
  --space-xl: 2rem;       /* 32px */
  --space-2xl: 3rem;      /* 48px */
  --space-3xl: 4rem;      /* 64px */
  --space-4xl: 6rem;      /* 96px */
  --space-5xl: 8rem;      /* 128px */

  --section-padding: clamp(4rem, 8vw, 8rem);
  --content-max-width: 1200px;
  --content-narrow-width: 800px;

  /* === Borders & Radius === */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-2xl: 24px;
  --radius-full: 9999px;

  /* === Shadows === */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.12);
  --shadow-glow: 0 0 30px rgba(46, 124, 246, 0.15);
  --shadow-card-hover: 0 12px 40px rgba(0, 0, 0, 0.12);

  /* === Transitions === */
  --transition-fast: 150ms ease;
  --transition-base: 300ms ease;
  --transition-slow: 500ms ease;
  --transition-spring: 500ms cubic-bezier(0.34, 1.56, 0.64, 1);

  /* === Z-index === */
  --z-loading: 9999;
  --z-header: 1000;
  --z-overlay: 900;
  --z-modal: 800;
  --z-dropdown: 700;
}

/* === Dark section variants === */
.section--dark {
  --color-text-primary: #FFFFFF;
  --color-text-secondary: #C0C4D0;
  --color-bg-base: #0D1117;
  --color-border: #2A2E3A;
}