:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --text-main: #1e293b;
    --text-muted: #64748b;
    --bg-light: #f8fafc;
}

/* Тёмная тема (по умолчанию) */
html[data-theme="dark"] {
    --text-main: #e2e8f0;
    --text-muted: #94a3b8;
    --bg-light: #1e293b;
    --bg-page: #0f172a;
    --bg-card: #1e293b;
    --bg-card-alt: #334155;
    --border-color: #334155;
    --hero-gradient: radial-gradient(circle at top right, #172554 0%, #0f172a 50%);
    --badge-bg: #1e3a8a;
    --badge-color: #93c5fd;
    --icon-bg: #1e3a8a;
    --shadow-card: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
    --shadow-faq: 0 2px 4px rgba(0,0,0,0.3);
    --security-border: #334155;
}

/* Светлая тема */
html[data-theme="light"] {
    --text-main: #1e293b;
    --text-muted: #64748b;
    --bg-light: #f8fafc;
    --bg-page: #ffffff;
    --bg-card: #ffffff;
    --bg-card-alt: #ffffff;
    --border-color: #e2e8f0;
    --hero-gradient: radial-gradient(circle at top right, #eff6ff 0%, #ffffff 50%);
    --badge-bg: #dbeafe;
    --badge-color: var(--primary);
    --icon-bg: #eff6ff;
    --shadow-card: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-faq: 0 2px 4px rgba(0,0,0,0.05);
    --security-border: #e2e8f0;
}

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

body {
    font-family: 'Inter', system-ui, sans-serif;
    color: var(--text-main);
    line-height: 1.6;
    overflow-x: hidden;
    background-color: var(--bg-page);
    transition: background-color 0.3s, color 0.3s;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* Header */
header {
    padding: 24px 0;
    position: absolute;
    width: 100%;
    z-index: 10;
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-right {
    display: flex;
    align-items: center;
    gap: 16px;
}

.logo {
    font-size: 24px;
    font-weight: 800;
    color: var(--primary);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 8px;
}

.btn-outline {
    padding: 10px 20px;
    border: 2px solid var(--primary);
    color: var(--primary);
    border-radius: 50px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s;
}

.btn-outline:hover {
    background: var(--primary);
    color: white;
}

/* Кнопка переключения темы */
.theme-toggle {
    background: none;
    border: 2px solid var(--primary);
    color: var(--primary);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s;
    flex-shrink: 0;
}

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

.theme-toggle svg {
    width: 20px;
    height: 20px;
    fill: currentColor;
}

/* Hero Section */
.hero {
    padding: 160px 0 100px;
    background: var(--hero-gradient);
    position: relative;
    transition: background 0.3s;
}

.hero-content {
    max-width: 700px;
}

.badge {
    display: inline-block;
    padding: 6px 12px;
    background: var(--badge-bg);
    color: var(--badge-color);
    border-radius: 50px;
    font-size: 14px;
    font-weight: 700;
    margin-bottom: 20px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    transition: background 0.3s, color 0.3s;
}

h1 {
    font-size: 56px;
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 24px;
    letter-spacing: -0.02em;
    color: var(--text-main);
}

h1 span {
    color: var(--primary);
}

.hero p {
    font-size: 20px;
    color: var(--text-muted);
    margin-bottom: 40px;
}

.btn-primary {
    display: inline-block;
    padding: 18px 36px;
    background: var(--primary);
    color: white;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 700;
    font-size: 18px;
    box-shadow: 0 10px 25px rgba(37, 99, 235, 0.3);
    transition: all 0.3s;
    cursor: pointer;
    border: none;
}

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 15px 30px rgba(37, 99, 235, 0.4);
}

/* Features */
.features {
    padding: 100px 0;
    background: var(--bg-light);
    transition: background 0.3s;
}

.section-title {
    text-align: center;
    max-width: 600px;
    margin: 0 auto 60px;
}

.section-title h2 {
    font-size: 36px;
    margin-bottom: 16px;
    color: var(--text-main);
}

.section-title p {
    color: var(--text-muted);
    font-size: 18px;
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 32px;
}

.grid-services {
    grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
}

.card {
    background: var(--bg-card);
    padding: 40px;
    border-radius: 24px;
    box-shadow: var(--shadow-card);
    transition: transform 0.3s, background 0.3s;
}

.card:hover {
    transform: translateY(-10px);
}

.icon {
    width: 48px;
    height: 48px;
    background: var(--icon-bg);
    color: var(--primary);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 24px;
    font-size: 24px;
    transition: background 0.3s;
}

.card h3 {
    margin-bottom: 12px;
    font-size: 20px;
    color: var(--text-main);
}

.card p {
    color: var(--text-muted);
}

/* How it works */
.how-it-works {
    padding: 100px 0;
    background: var(--bg-page);
    transition: background 0.3s;
}

.steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-top: 60px;
}

.step {
    text-align: center;
    position: relative;
}

.step-number {
    width: 64px;
    height: 64px;
    background: var(--primary);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    font-weight: 800;
    margin: 0 auto 20px;
}

.step h3 {
    font-size: 20px;
    margin-bottom: 12px;
    color: var(--text-main);
}

.step p {
    color: var(--text-muted);
}

/* Results section */
.results {
    padding: 80px 0;
    background: var(--bg-light);
    transition: background 0.3s;
}

.stats {
    display: flex;
    justify-content: space-around;
    flex-wrap: wrap;
    gap: 40px;
    text-align: center;
}

.stat-item h4 {
    font-size: 48px;
    color: var(--primary);
    margin-bottom: 8px;
}

.stat-item p {
    font-weight: 600;
    color: var(--text-muted);
}

/* Services / Pricing section */
.services {
    padding: 100px 0;
    background: var(--bg-page);
    transition: background 0.3s;
}

.service-card {
    background: var(--bg-card);
    border-radius: 20px;
    padding: 36px;
    box-shadow: var(--shadow-card);
    transition: transform 0.3s, background 0.3s, box-shadow 0.3s;
    display: flex;
    flex-direction: column;
    border: 2px solid var(--border-color);
}

.service-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 12px 24px rgba(0, 0, 0, 0.15);
    border-color: var(--primary);
}

.service-card.featured {
    border-color: var(--primary);
    position: relative;
}

.service-card.featured::before {
    content: 'Популярный';
    position: absolute;
    top: -12px;
    right: 24px;
    background: var(--primary);
    color: white;
    padding: 4px 16px;
    border-radius: 50px;
    font-size: 12px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.service-model {
    font-size: 13px;
    font-weight: 700;
    color: var(--primary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 8px;
}

.service-name {
    font-size: 22px;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text-main);
    line-height: 1.3;
}

.service-desc {
    font-size: 14px;
    color: var(--text-muted);
    line-height: 1.6;
    margin-bottom: 20px;
    flex: 1;
}

.service-specs {
    display: flex;
    gap: 16px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.service-spec {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 13px;
    color: var(--text-muted);
    background: var(--bg-light);
    padding: 6px 12px;
    border-radius: 8px;
}

.service-spec strong {
    color: var(--text-main);
}

.service-price-block {
    margin-bottom: 20px;
}

.service-price {
    font-size: 36px;
    font-weight: 800;
    color: var(--text-main);
    line-height: 1;
}

.service-price-label {
    font-size: 13px;
    color: var(--text-muted);
    margin-top: 4px;
}

.service-monthly {
    font-size: 15px;
    color: var(--text-muted);
    margin-bottom: 16px;
}

.service-monthly strong {
    color: var(--text-main);
}

.billing-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    margin-top: 20px;
}

.billing-label {
    font-size: 15px;
    color: var(--text-muted);
    cursor: pointer;
    transition: color 0.3s;
}

.billing-label.billing-active {
    color: var(--text-main);
    font-weight: 600;
}

.billing-discount {
    display: inline-block;
    background: #22c55e;
    color: #fff;
    font-size: 11px;
    font-weight: 700;
    padding: 2px 6px;
    border-radius: 6px;
    margin-left: 4px;
}

.toggle-switch {
    position: relative;
    display: inline-block;
    width: 44px;
    height: 24px;
    cursor: pointer;
}

.toggle-switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.toggle-slider {
    position: absolute;
    inset: 0;
    background: var(--border-color);
    border-radius: 24px;
    transition: background 0.3s;
}

.toggle-slider::before {
    content: '';
    position: absolute;
    width: 18px;
    height: 18px;
    left: 3px;
    bottom: 3px;
    background: #fff;
    border-radius: 50%;
    transition: transform 0.3s;
}

.toggle-switch input:checked + .toggle-slider {
    background: var(--accent, #3b82f6);
}

.toggle-switch input:checked + .toggle-slider::before {
    transform: translateX(20px);
}

.service-btn {
    display: block;
    text-align: center;
    padding: 14px 24px;
    background: var(--primary);
    color: white;
    border-radius: 12px;
    text-decoration: none;
    font-weight: 700;
    font-size: 15px;
    transition: all 0.3s;
    border: none;
    cursor: pointer;
}

.service-btn:hover {
    background: var(--primary-dark);
    transform: translateY(-1px);
}

.service-btn.outline {
    background: transparent;
    color: var(--primary);
    border: 2px solid var(--primary);
}

.service-btn.outline:hover {
    background: var(--primary);
    color: white;
}

/* Security section */
.security {
    padding: 100px 0;
    background: var(--bg-page);
    transition: background 0.3s;
}

.security-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 32px;
    margin-top: 60px;
}

.security-card {
    background: var(--bg-card);
    padding: 32px;
    border-radius: 20px;
    border: 2px solid var(--security-border);
    transition: border-color 0.3s, background 0.3s;
}

.security-card:hover {
    border-color: var(--primary);
}

.security-card h3 {
    font-size: 18px;
    margin-bottom: 12px;
    color: var(--text-main);
}

.security-card p {
    color: var(--text-muted);
    font-size: 15px;
}

/* FAQ */
.faq {
    padding: 100px 0;
    background: var(--bg-light);
    transition: background 0.3s;
}

.faq-list {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    background: var(--bg-card);
    border-radius: 12px;
    margin-bottom: 16px;
    overflow: hidden;
    box-shadow: var(--shadow-faq);
    transition: background 0.3s;
}

.faq-item summary {
    padding: 20px 24px;
    font-weight: 600;
    font-size: 17px;
    cursor: pointer;
    list-style: none;
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: var(--text-main);
}

.faq-item summary::after {
    content: '+';
    font-size: 24px;
    color: var(--primary);
    transition: transform 0.2s;
}

.faq-item[open] summary::after {
    transform: rotate(45deg);
}

.faq-item .faq-answer {
    padding: 0 24px 20px;
    color: var(--text-muted);
    font-size: 15px;
    line-height: 1.7;
}

.faq-item .faq-answer a {
    color: var(--primary);
}

.faq-item .faq-answer code {
    background: var(--bg-card-alt);
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 14px;
}

/* CTA Section */
.cta-box {
    background: var(--primary);
    border-radius: 32px;
    padding: 60px;
    color: white;
    text-align: center;
    margin: 80px 0;
}

.cta-box h2 {
    font-size: 40px;
    margin-bottom: 24px;
}

.cta-box p {
    font-size: 18px;
    opacity: 0.9;
    margin-bottom: 30px;
}

.cta-box .btn-white {
    background: white;
    color: var(--primary);
    padding: 18px 40px;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 700;
    display: inline-block;
}

footer {
    padding: 60px 0;
    border-top: 1px solid var(--border-color);
    text-align: center;
    color: var(--text-muted);
    transition: border-color 0.3s;
}

/* Планшеты и малые экраны */
@media (max-width: 768px) {
    .container {
        padding: 0 16px;
    }

    header {
        padding: 16px 0;
    }

    h1 { font-size: 34px; }
    .hero { padding: 120px 0 60px; }
    .hero p { font-size: 17px; margin-bottom: 28px; }
    .badge { font-size: 12px; padding: 5px 10px; }

    .section-title { margin-bottom: 40px; }
    .section-title h2 { font-size: 26px; }
    .section-title p { font-size: 16px; }

    .features, .services, .how-it-works, .security, .faq { padding: 60px 0; }
    .results { padding: 48px 0; }
    .stats { gap: 24px; }
    .stat-item h4 { font-size: 34px; }

    .grid, .security-grid { gap: 16px; }
    .card { padding: 24px; border-radius: 18px; }
    .card:hover { transform: none; }
    .icon { width: 40px; height: 40px; font-size: 20px; margin-bottom: 16px; }

    .service-card { padding: 24px; }
    .service-price { font-size: 28px; }
    .service-name { font-size: 19px; }

    .steps { gap: 28px; margin-top: 40px; }
    .security-grid { margin-top: 40px; }

    .faq-item summary { padding: 16px 18px; font-size: 15px; }
    .faq-item .faq-answer { padding: 0 18px 16px; }

    .cta-box { padding: 40px 20px; border-radius: 24px; margin: 56px 0; }
    .cta-box h2 { font-size: 26px; }
    .cta-box p { font-size: 16px; }
    .cta-box .btn-white { padding: 14px 28px; }

    footer { padding: 40px 0; }
}

/* Телефоны */
@media (max-width: 480px) {
    /* Шапка: ширина задаётся кнопками, лого сжимается */
    nav { gap: 8px; }
    .logo {
        font-size: 15px;
        gap: 6px;
        white-space: nowrap;
        flex: 0 1 auto;
        min-width: 0;
    }
    .logo svg { width: 24px; height: 24px; flex-shrink: 0; }
    .nav-right { gap: 6px; flex-shrink: 0; }
    .btn-outline { padding: 6px 10px; font-size: 12px; border-width: 1.5px; white-space: nowrap; }
    .theme-toggle { width: 32px; height: 32px; border-width: 1.5px; flex-shrink: 0; }
    .theme-toggle svg { width: 15px; height: 15px; }

    /* Hero */
    .hero { padding: 104px 0 48px; }
    h1 { font-size: 27px; line-height: 1.2; margin-bottom: 16px; }
    .badge { display: block; width: fit-content; font-size: 11px; margin-bottom: 16px; }
    .hero p { font-size: 15px; margin-bottom: 24px; }
    .btn-primary {
        display: block;
        width: 100%;
        padding: 15px 20px;
        font-size: 16px;
    }

    /* Сетки в одну колонку без overflow */
    .grid,
    .grid-services,
    .security-grid {
        grid-template-columns: 1fr;
    }

    .stats { gap: 20px; }
    .stat-item { min-width: 40%; }
    .stat-item h4 { font-size: 30px; }
    .stat-item p { font-size: 13px; }

    .service-card { padding: 20px; }
    .service-card.featured::before { right: 16px; }
    .service-price { font-size: 26px; }

    .billing-toggle { flex-wrap: wrap; gap: 8px; }
}