/* Базовые переменные */
:root {
    /* Тёмная тема (по умолчанию) */
    --bg-body: #0a0c10;
    --bg-card: #14171c;
    --bg-header: #1a1218;
    --bg-alt: #0f1115;
    --text-primary: #e4e6eb;
    --text-secondary: #9a8f8f;
    --text-muted: #b0b0c0;
    --border-color: #2c2121;
    --accent: #8b2c2c;
    --accent-hover: #a13e3e;
    --accent-light: #e0a0a0;
    --warning-bg: #2c1e1e;
    --warning-border: #b33b3b;
    --code-bg: #0a0c10;
    --badge-official-bg: #2c3e50;
    --badge-official-text: #ecf0f1;
    --badge-custom-bg: #8b2c2c;
    --badge-custom-text: #ffffff;
}

.light-theme {
    /* Светлая тема */
    --bg-body: #f5f7fa;
    --bg-card: #ffffff;
    --bg-header: #f0f0f0;
    --bg-alt: #f8f9fa;
    --text-primary: #1a1a2e;
    --text-secondary: #4a4a5a;
    --text-muted: #6c6c7a;
    --border-color: #d1d1e0;
    --accent: #c0392b;
    --accent-hover: #e74c3c;
    --accent-light: #e0a0a0;
    --warning-bg: #fdecea;
    --warning-border: #e74c3c;
    --code-bg: #f0f2f5;
    --badge-official-bg: #3498db;
    --badge-official-text: #ffffff;
    --badge-custom-bg: #c0392b;
    --badge-custom-text: #ffffff;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
    line-height: 1.6;
    background-color: var(--bg-body);
    color: var(--text-primary);
    transition: background-color 0.3s, color 0.3s;
}

.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
}

/* Header & navigation */
header {
    background-color: var(--bg-header);
    border-bottom: 2px solid var(--accent);
    padding: 1rem 0;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    transition: background-color 0.3s;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--accent);
    text-decoration: none;
    letter-spacing: 1px;
    transition: color 0.3s;
}

.logo:hover {
    color: var(--accent-hover);
}

.nav-links {
    list-style: none;
    display: flex;
    gap: 1.5rem;
    align-items: center;
}

.nav-links a {
    color: var(--text-primary);
    text-decoration: none;
    transition: color 0.3s;
    font-weight: 500;
}

.nav-links a:hover {
    color: var(--accent-light);
}

/* Theme toggle button */
.theme-toggle {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 30px;
    padding: 0.4rem 1rem;
    cursor: pointer;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-primary);
    transition: all 0.2s;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

.theme-toggle:hover {
    background: var(--accent);
    color: white;
    border-color: var(--accent);
}

/* Main content */
main {
    min-height: calc(100vh - 140px);
    padding: 2rem 0;
}

h1, h2, h3 {
    margin-bottom: 1rem;
    font-weight: 600;
}

h1 {
    font-size: 2rem;
    color: var(--text-primary);
    border-left: 4px solid var(--accent);
    padding-left: 1rem;
}

h2 {
    color: var(--text-primary);
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.5rem;
}

h3 {
    color: var(--text-primary);
}

/* Hero section */
.hero {
    background: linear-gradient(135deg, var(--bg-header), var(--bg-body));
    color: var(--text-primary);
    padding: 4rem 0;
    text-align: center;
    margin-bottom: 2rem;
    border-radius: 0 0 20px 20px;
    border-bottom: 1px solid var(--border-color);
}

.hero h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    border-left: none;
    padding-left: 0;
}

.hero p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
    opacity: 0.9;
    color: var(--text-secondary);
}

.btn {
    display: inline-block;
    background-color: var(--accent);
    color: white;
    padding: 0.75rem 1.5rem;
    text-decoration: none;
    border-radius: 30px;
    transition: background-color 0.3s, transform 0.1s;
    font-weight: bold;
    box-shadow: 0 2px 5px rgba(0,0,0,0.2);
}

.btn:hover {
    background-color: var(--accent-hover);
    transform: translateY(-2px);
}

/* Features grid */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.feature-card {
    background: var(--bg-card);
    padding: 1.5rem;
    border-radius: 12px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
    text-align: center;
    border: 1px solid var(--border-color);
    transition: transform 0.2s, border-color 0.2s;
}

.feature-card:hover {
    transform: translateY(-5px);
    border-color: var(--accent);
}

.feature-card h3 {
    margin-bottom: 0.5rem;
    color: var(--accent-light);
}

/* ISO grid */
.iso-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.iso-card {
    background: var(--bg-card);
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
    border: 1px solid var(--border-color);
}

.iso-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 14px rgba(0,0,0,0.15);
    border-color: var(--accent);
}

.iso-card h3 {
    color: var(--accent-light);
    margin-bottom: 0.5rem;
}

.iso-card .meta {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-bottom: 0.75rem;
    border-bottom: 1px dashed var(--border-color);
    padding-bottom: 0.5rem;
}

.iso-card .description {
    margin: 0.75rem 0;
    color: var(--text-muted);
}

.iso-card .download-link {
    display: inline-block;
    background-color: var(--accent);
    color: white;
    padding: 0.5rem 1rem;
    text-decoration: none;
    border-radius: 30px;
    margin-top: 0.5rem;
    transition: background-color 0.3s;
    font-weight: 500;
}

.iso-card .download-link:hover {
    background-color: var(--accent-hover);
}

/* Badges */
.badge {
    display: inline-block;
    padding: 2px 8px;
    border-radius: 20px;
    font-size: 0.7rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.badge.official {
    background: var(--badge-official-bg);
    color: var(--badge-official-text);
    border: 1px solid var(--border-color);
}

.badge.custom {
    background: var(--badge-custom-bg);
    color: var(--badge-custom-text);
    border: 1px solid var(--border-color);
}

/* Format page */
.format-section {
    background: var(--bg-card);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 2px 12px rgba(0,0,0,0.1);
    border: 1px solid var(--border-color);
}

.format-section h2 {
    margin-top: 1.5rem;
}

.format-section h3 {
    margin-top: 1rem;
}

.warning {
    background: var(--warning-bg);
    border-left: 4px solid var(--warning-border);
    padding: 1rem;
    border-radius: 6px;
    margin: 1rem 0;
    font-weight: normal;
    color: var(--text-primary);
}

pre {
    background-color: var(--code-bg);
    color: var(--text-primary);
    padding: 0.75rem;
    border-radius: 8px;
    overflow-x: auto;
    font-family: 'Fira Code', monospace;
    border: 1px solid var(--border-color);
}

code {
    font-family: monospace;
    background: var(--bg-alt);
    padding: 0.2rem 0.4rem;
    border-radius: 4px;
    color: var(--accent-light);
}

/* Tabs */
.tabs {
    display: flex;
    gap: 0.5rem;
    margin: 1.5rem 0 2rem 0;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.5rem;
}

.tab-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    padding: 0.5rem 1rem;
    font-size: 1rem;
    cursor: pointer;
    transition: color 0.2s;
    font-weight: 500;
}

.tab-btn:hover {
    color: var(--accent-light);
}

.tab-btn.active {
    color: var(--text-primary);
    border-bottom: 2px solid var(--accent);
    margin-bottom: -1px;
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

/* Steps */
.steps {
    display: flex;
    flex-direction: column;
    gap: 1.2rem;
    margin-bottom: 2rem;
}

.step {
    display: flex;
    gap: 1rem;
    align-items: flex-start;
    background: var(--bg-alt);
    padding: 1rem;
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.step-num {
    background: var(--border-color);
    color: var(--accent-light);
    width: 32px;
    height: 32px;
    border-radius: 20px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    font-size: 0.9rem;
    flex-shrink: 0;
}

.step-desc {
    flex: 1;
}

.step-desc strong {
    color: var(--text-primary);
    display: block;
    margin-bottom: 0.25rem;
}

.step-desc p {
    margin: 0.2rem 0;
    font-size: 0.9rem;
    color: var(--text-muted);
}

.step-desc pre {
    margin: 0.5rem 0;
}

.alternative {
    background: var(--bg-alt);
    padding: 0.8rem 1rem;
    border-radius: 8px;
    border-left: 3px solid var(--accent);
    font-size: 0.9rem;
}

.alternative a {
    color: var(--accent-light);
    text-decoration: none;
}

.alternative a:hover {
    text-decoration: underline;
}

/* Footer */
footer {
    background-color: var(--bg-header);
    color: var(--text-secondary);
    text-align: center;
    padding: 1.5rem 0;
    margin-top: 2rem;
    border-top: 1px solid var(--border-color);
    transition: background-color 0.3s;
}

/* Responsive */
@media (max-width: 768px) {
    .nav-container {
        flex-direction: column;
        text-align: center;
    }
    
    .hero h1 {
        font-size: 1.8rem;
    }
    
    .hero p {
        font-size: 1rem;
    }
    
    .iso-grid {
        grid-template-columns: 1fr;
    }
    
    .step {
        flex-direction: column;
    }
    
    .step-num {
        align-self: flex-start;
    }
}
    border-bottom: 1px dashed #2c2121;
    padding-bottom: 0.5rem;
}
/* Survey page */
.survey-intro {
    margin-bottom: 2rem;
    font-size: 1.1rem;
    color: var(--text-secondary);
}

.survey-form {
    background: var(--bg-card);
    padding: 2rem;
    border-radius: 12px;
    border: 1px solid var(--border-color);
}

.form-group {
    margin-bottom: 1.8rem;
}

.form-group label {
    display: block;
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--text-primary);
}

.required {
    color: var(--accent);
}

.form-group input[type="text"],
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background: var(--bg-body);
    color: var(--text-primary);
    font-family: inherit;
    font-size: 1rem;
    transition: border-color 0.2s;
}

.form-group input[type="text"]:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--accent);
}

.radio-group {
    display: flex;
    flex-direction: column;
    gap: 0.6rem;
}

.radio-group label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: normal;
    cursor: pointer;
}

.radio-group input[type="radio"] {
    cursor: pointer;
    accent-color: var(--accent);
}

.success-message {
    text-align: center;
    padding: 3rem 2rem;
    background: var(--bg-card);
    border-radius: 12px;
    border: 1px solid var(--border-color);
}

.success-message h1 {
    margin-bottom: 1rem;
}

.success-message p {
    margin-bottom: 2rem;
    font-size: 1.1rem;
}