/**
 * CSS Variables
 * TOEIC Vocabulary List - UI v1
 */

:root {
    /* Colors - Primary */
    --color-primary: #2563eb;
    --color-primary-dark: #1e40af;
    --color-primary-light: #3b82f6;

    /* Colors - Secondary */
    --color-secondary: #64748b;
    --color-secondary-dark: #475569;
    --color-secondary-light: #94a3b8;

    /* Colors - Background */
    --color-bg-page: #f8fafc;
    --color-bg-card: #ffffff;
    --color-bg-header: #1e293b;
    --color-bg-footer: #0f172a;

    /* Colors - Text */
    --color-text-primary: #1e293b;
    --color-text-secondary: #64748b;
    --color-text-light: #94a3b8;
    --color-text-inverse: #ffffff;

    /* Colors - Border */
    --color-border: #e2e8f0;
    --color-border-hover: #cbd5e1;

    /* Colors - Relationship Types */
    --color-derivative: #8b5cf6;    /* 派生語 - 紫 */
    --color-synonym: #10b981;       /* 類義語 - 緑 */
    --color-antonym: #ef4444;       /* 反意語 - 赤 */

    /* Colors - Status */
    --color-success: #10b981;
    --color-error: #ef4444;
    --color-warning: #f59e0b;
    --color-info: #3b82f6;

    /* Typography - Font Families */
    --font-family-base: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue', sans-serif;
    --font-family-code: 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, Courier, monospace;

    /* Typography - Font Sizes */
    --font-size-xs: 0.75rem;      /* 12px */
    --font-size-sm: 0.875rem;     /* 14px */
    --font-size-base: 1rem;       /* 16px */
    --font-size-lg: 1.125rem;     /* 18px */
    --font-size-xl: 1.25rem;      /* 20px */
    --font-size-2xl: 1.5rem;      /* 24px */
    --font-size-3xl: 1.875rem;    /* 30px */
    --font-size-4xl: 2.25rem;     /* 36px */

    /* Typography - Font Weights */
    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;

    /* Typography - Line Heights */
    --line-height-tight: 1.25;
    --line-height-normal: 1.5;
    --line-height-relaxed: 1.75;

    /* Spacing */
    --spacing-xs: 0.25rem;        /* 4px */
    --spacing-sm: 0.5rem;         /* 8px */
    --spacing-md: 1rem;           /* 16px */
    --spacing-lg: 1.5rem;         /* 24px */
    --spacing-xl: 2rem;           /* 32px */
    --spacing-2xl: 3rem;          /* 48px */
    --spacing-3xl: 4rem;          /* 64px */

    /* Border Radius */
    --radius-sm: 0.25rem;         /* 4px */
    --radius-md: 0.5rem;          /* 8px */
    --radius-lg: 0.75rem;         /* 12px */
    --radius-xl: 1rem;            /* 16px */
    --radius-full: 9999px;

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

    /* Transitions */
    --transition-fast: 150ms ease-in-out;
    --transition-base: 300ms ease-in-out;
    --transition-slow: 500ms ease-in-out;

    /* Z-index */
    --z-index-base: 1;
    --z-index-dropdown: 100;
    --z-index-sticky: 200;
    --z-index-fixed: 300;
    --z-index-modal: 400;
    --z-index-popover: 500;
    --z-index-tooltip: 600;

    /* Container Width */
    --container-max-width: 1200px;

    /* Breakpoints (for reference, use in @media queries) */
    --breakpoint-sm: 640px;
    --breakpoint-md: 768px;
    --breakpoint-lg: 1024px;
    --breakpoint-xl: 1280px;
}