/**
 * Design System v1.0 — Future 2026
 * Токены и базовые стили
 */

/* ========================================
   CSS Custom Properties (Tokens)
   ======================================== */

:root {
    /* Colors: Base */
    --color-white: #ffffff;
    --color-black: #000000;

    /* Colors: Gray Scale */
    --color-gray-50: #f9fafb;
    --color-gray-100: #f3f4f6;
    --color-gray-200: #e5e7eb;
    --color-gray-300: #d1d5db;
    --color-gray-400: #9ca3af;
    --color-gray-500: #6b7280;
    --color-gray-600: #4b5563;
    --color-gray-700: #374151;
    --color-gray-800: #1f2937;
    --color-gray-900: #111827;

    /* Colors: Primary */
    --color-primary-50: #eff6ff;
    --color-primary-100: #dbeafe;
    --color-primary-200: #bfdbfe;
    --color-primary-300: #93c5fd;
    --color-primary-400: #60a5fa;
    --color-primary-500: #3b82f6;
    --color-primary-600: #2563eb;
    --color-primary-700: #1d4ed8;
    --color-primary-800: #1e40af;
    --color-primary-900: #1e3a8a;

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

    /* Typography */
    --font-family-base: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    --font-family-mono: "SF Mono", "Fira Code", "Fira Mono", Consolas, monospace;

    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size-4xl: 2.25rem;

    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;

    --line-height-tight: 1.25;
    --line-height-normal: 1.5;
    --line-height-relaxed: 1.75;

    /* Spacing */
    --spacing-0: 0;
    --spacing-1: 0.25rem;
    --spacing-2: 0.5rem;
    --spacing-3: 0.75rem;
    --spacing-4: 1rem;
    --spacing-5: 1.25rem;
    --spacing-6: 1.5rem;
    --spacing-8: 2rem;
    --spacing-10: 2.5rem;
    --spacing-12: 3rem;
    --spacing-16: 4rem;
    --spacing-20: 5rem;

    /* Layout */
    --container-max: 1200px;
    --container-padding: var(--spacing-4);

    /* Borders */
    --border-radius-sm: 0.25rem;
    --border-radius-md: 0.375rem;
    --border-radius-lg: 0.5rem;
    --border-radius-xl: 0.75rem;
    --border-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);

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
    --transition-slow: 350ms ease;

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

/* ========================================
   Reset & Base
   ======================================== */

*,
*::before,
*::after {
    box-sizing: border-box;
}

html {
    font-size: 16px;
    -webkit-text-size-adjust: 100%;
}

body {
    margin: 0;
    padding: 0;
    font-family: var(--font-family-base);
    font-size: var(--font-size-base);
    font-weight: var(--font-weight-normal);
    line-height: var(--line-height-normal);
    color: var(--color-gray-900);
    background-color: var(--color-white);
}

h1, h2, h3, h4, h5, h6 {
    margin-top: 0;
    margin-bottom: var(--spacing-4);
    font-weight: var(--font-weight-semibold);
    line-height: var(--line-height-tight);
}

h1 { font-size: var(--font-size-4xl); }
h2 { font-size: var(--font-size-3xl); }
h3 { font-size: var(--font-size-2xl); }
h4 { font-size: var(--font-size-xl); }
h5 { font-size: var(--font-size-lg); }
h6 { font-size: var(--font-size-base); }

p {
    margin-top: 0;
    margin-bottom: var(--spacing-4);
}

a {
    color: var(--color-primary-600);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--color-primary-700);
    text-decoration: underline;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

ul, ol {
    margin-top: 0;
    margin-bottom: var(--spacing-4);
    padding-left: var(--spacing-6);
}

/* ========================================
   Utility Classes
   ======================================== */

.container {
    width: 100%;
    max-width: var(--container-max);
    margin-left: auto;
    margin-right: auto;
    padding-left: var(--container-padding);
    padding-right: var(--container-padding);
}

.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

.clearfix::after {
    content: "";
    display: table;
    clear: both;
}