:root {
    /* Colors */
    --primary-blue: #0078d4;
    --secondary-blue: #106ebe;
    --accent-teal: #00a4a6;
    --accent-green: #00c853;
    --accent-orange: #ff6b00;
    --bg-white: #ffffff;
    --bg-light: #f5f7fa;
    --bg-lighter: #fafbfc;
    --text-dark: #1f1f1f;
    --text-medium: #4a5568;
    --text-light: #718096;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 15px rgba(0,0,0,0.1);
    --shadow-xl: 0 20px 25px rgba(0,0,0,0.15);

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

    /* Border Radius */
    --radius-sm: 6px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;

    /* Typography */
    --font-sans: 'Segoe UI', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-size-xs: 12px;
    --font-size-sm: 14px;
    --font-size-base: 16px;
    --font-size-lg: 18px;
    --font-size-xl: 20px;
    --font-size-2xl: 24px;
    --font-size-3xl: 30px;
    --font-size-4xl: 36px;
    --font-size-5xl: 48px;
}

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

body {
    font-family: var(--font-sans);
    font-size: var(--font-size-lg);
    line-height: 1.7;
    color: var(--text-dark);
    background: var(--bg-lighter);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    transition: background 1s ease, color 1s ease;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

/* Header */
header {
    background: var(--bg-white);
    border-bottom: 1px solid var(--border-color);
    padding: var(--spacing-md) 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: var(--shadow-sm);
    transition: background 1s ease, border-color 1s ease;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.logo-section {
    flex: 1;
    min-width: 200px;
}

.main-nav {
    display: flex;
    gap: var(--spacing-lg);
    align-items: center;
}

.nav-link {
    color: var(--text-dark);
    text-decoration: none;
    font-size: var(--font-size-base);
    font-weight: 600;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-sm);
    transition: all 0.2s ease;
}

.nav-link:hover {
    color: var(--primary-blue);
    background: var(--bg-light);
}

.nav-link.active {
    color: var(--primary-blue);
    background: var(--bg-light);
}

.logo {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-blue) 0%, var(--accent-teal) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.5px;
    margin-bottom: var(--spacing-xs);
}

.tagline {
    font-size: var(--font-size-sm);
    color: var(--text-medium);
    font-weight: 500;
    transition: color 1s ease;
}

.language-switcher {
    display: flex;
    gap: var(--spacing-xs);
    background: var(--bg-light);
    padding: var(--spacing-xs);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
}

.lang-btn {
    padding: var(--spacing-sm) var(--spacing-md);
    border: none;
    background: transparent;
    color: var(--text-medium);
    cursor: pointer;
    font-size: var(--font-size-sm);
    font-family: var(--font-sans);
    font-weight: 600;
    border-radius: var(--radius-sm);
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

.lang-btn:hover {
    background: var(--bg-white);
    color: var(--primary-blue);
}

.lang-btn.active {
    background: var(--primary-blue);
    color: var(--bg-white);
    box-shadow: var(--shadow-sm);
}

/* Hero */
.hero {
    background: linear-gradient(135deg, #e6f2ff 0%, #cce5ff 50%, #b3d9ff 100%);
    padding: var(--spacing-3xl) 0;
    position: relative;
    overflow: hidden;
    transition: background 1s ease;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -10%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(0,164,166,0.08) 0%, transparent 70%);
    border-radius: 50%;
}

.hero-content {
    max-width: 900px;
    margin: 0 auto;
    text-align: center;
    position: relative;
    z-index: 1;
}

.hero h1 {
    font-size: var(--font-size-5xl);
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: var(--spacing-lg);
    line-height: 1.2;
    letter-spacing: -1px;
    transition: color 1s ease, text-shadow 1s ease;
}

.hero p {
    font-size: var(--font-size-xl);
    color: var(--text-medium);
    margin-bottom: var(--spacing-md);
    line-height: 1.6;
    transition: color 1s ease;
}

.primary-cta {
    background: linear-gradient(135deg, var(--primary-blue) 0%, var(--secondary-blue) 100%);
    color: var(--bg-white);
    padding: var(--spacing-md) var(--spacing-2xl);
    border: none;
    font-size: var(--font-size-lg);
    font-weight: 600;
    cursor: pointer;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease;
    margin-top: var(--spacing-lg);
    position: relative;
    z-index: 10;
    -webkit-tap-highlight-color: transparent;
    touch-action: manipulation;
}

.primary-cta:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.primary-cta:active {
    transform: translateY(0);
}

.hero-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-2xl);
}

.stat-item {
    background: var(--bg-white);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1), background 1s ease;
}

.stat-item:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
    border-color: var(--primary-blue);
}

.stat-number {
    font-size: var(--font-size-4xl);
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-blue) 0%, var(--accent-teal) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    display: block;
    margin-bottom: var(--spacing-xs);
}

.stat-label {
    font-size: var(--font-size-base);
    color: var(--text-medium);
    font-weight: 500;
    transition: color 1s ease;
}

/* Section */
.section {
    padding: var(--spacing-3xl) 0;
}

.section-alt {
    background: var(--bg-white);
    transition: background 1s ease;
}

.section-title {
    font-size: var(--font-size-4xl);
    font-weight: 700;
    text-align: center;
    margin-bottom: var(--spacing-md);
    color: var(--text-dark);
    letter-spacing: -0.5px;
    transition: color 1s ease, text-shadow 1s ease;
}

.section-subtitle {
    font-size: var(--font-size-lg);
    text-align: center;
    color: var(--text-medium);
    margin-bottom: var(--spacing-2xl);
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
    transition: color 1s ease;
}

/* Services Grid */
.services-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
    gap: var(--spacing-lg);
}

.service-card {
    background: var(--bg-white);
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    border: 1px solid var(--border-color);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1), background 1s ease, border-color 1s ease;
    position: relative;
    overflow: hidden;
}

.service-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 0;
    background: linear-gradient(180deg, var(--primary-blue) 0%, var(--accent-teal) 100%);
    transition: height 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.service-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-xl);
    border-color: var(--primary-blue);
}

.service-card:hover::before {
    height: 100%;
}

.service-card h3 {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--primary-blue);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    transition: color 1s ease, text-shadow 1s ease;
}

.service-icon {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--primary-blue) 0%, var(--accent-teal) 100%);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--font-size-xl);
    flex-shrink: 0;
}

.service-card p {
    color: var(--text-medium);
    font-size: var(--font-size-base);
    line-height: 1.7;
    transition: color 1s ease;
}

/* Why Grid */
.why-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
}

.why-item {
    background: var(--bg-white);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    border-left: 4px solid var(--accent-teal);
    box-shadow: var(--shadow-sm);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1), background 1s ease, border-color 1s ease;
}

.why-item:hover {
    box-shadow: var(--shadow-lg);
    transform: translateX(4px);
    border-left-color: var(--primary-blue);
}

.why-item h3 {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--text-dark);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    transition: color 1s ease, text-shadow 1s ease;
}

.why-icon {
    width: 36px;
    height: 36px;
    background: linear-gradient(135deg, var(--primary-blue) 0%, var(--accent-teal) 100%);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--bg-white);
    font-size: var(--font-size-lg);
    font-weight: 700;
    flex-shrink: 0;
}

.why-item p {
    color: var(--text-medium);
    font-size: var(--font-size-base);
    line-height: 1.7;
    transition: color 1s ease;
}

/* How I Work Section */
.how-i-work {
    background: linear-gradient(135deg, #e6f2ff 0%, var(--bg-white) 100%);
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    border: 2px solid var(--primary-blue);
    margin-top: var(--spacing-2xl);
    box-shadow: var(--shadow-md);
    transition: background 1s ease, border-color 1s ease;
}

.how-i-work h3 {
    font-size: var(--font-size-2xl);
    font-weight: 600;
    margin-bottom: var(--spacing-lg);
    color: var(--primary-blue);
    transition: color 1s ease, text-shadow 1s ease;
}

.how-i-work p {
    color: var(--text-medium);
    margin-bottom: var(--spacing-md);
    transition: color 1s ease;
}

.how-i-work p:last-child {
    margin-bottom: 0;
}

/* Contact Section */
.contact-content {
    max-width: 700px;
    margin: 0 auto;
}

.contact-info {
    background: linear-gradient(135deg, var(--bg-white) 0%, #e6f2ff 100%);
    padding: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
    border-radius: var(--radius-xl);
    border: 2px solid var(--primary-blue);
    box-shadow: var(--shadow-md);
    transition: background 1s ease, border-color 1s ease;
}

.contact-info-item {
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-lg);
    border-bottom: 2px solid rgba(0,120,212,0.1);
    transition: color 1s ease;
}

.contact-info-item:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

.contact-info-item strong {
    display: block;
    margin-bottom: var(--spacing-sm);
    color: var(--primary-blue);
    font-size: var(--font-size-lg);
    font-weight: 600;
    transition: color 1s ease, text-shadow 1s ease;
}

.contact-info-item a {
    color: var(--accent-teal);
    text-decoration: none;
    font-size: var(--font-size-lg);
    font-weight: 500;
    transition: all 0.2s;
}

.contact-info-item a:hover {
    color: var(--primary-blue);
    text-decoration: underline;
}

/* Contact Form */
.contact-form {
    background: var(--bg-white);
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-md);
    transition: background 1s ease, border-color 1s ease;
}

.contact-form h3 {
    margin-bottom: var(--spacing-lg);
    font-weight: 600;
    color: var(--primary-blue);
    font-size: var(--font-size-2xl);
    transition: color 1s ease, text-shadow 1s ease;
}

.form-group {
    margin-bottom: var(--spacing-lg);
}

.form-group label {
    display: block;
    margin-bottom: var(--spacing-sm);
    color: var(--text-dark);
    font-weight: 600;
    font-size: var(--font-size-base);
    transition: color 1s ease;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: var(--spacing-md);
    border: 2px solid var(--border-color);
    background: var(--bg-lighter);
    font-family: var(--font-sans);
    font-size: var(--font-size-base);
    color: var(--text-dark);
    border-radius: var(--radius-md);
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-blue);
    background: var(--bg-white);
    box-shadow: 0 0 0 4px rgba(0,120,212,0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 150px;
}

.submit-btn {
    background: linear-gradient(135deg, var(--primary-blue) 0%, var(--secondary-blue) 100%);
    color: var(--bg-white);
    padding: var(--spacing-md) var(--spacing-2xl);
    border: none;
    font-size: var(--font-size-lg);
    font-weight: 600;
    cursor: pointer;
    font-family: var(--font-sans);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-md);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.submit-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.submit-btn:active {
    transform: translateY(0);
}

.form-message {
    margin-top: var(--spacing-lg);
    padding: var(--spacing-md);
    display: none;
    border-radius: var(--radius-md);
    font-size: var(--font-size-base);
}

.form-message.success {
    background: linear-gradient(135deg, #e7f7e7 0%, #d4f1d4 100%);
    color: #2d7a2d;
    border: 2px solid #b3e0b3;
}

.form-message.error {
    background: linear-gradient(135deg, #ffe7e7 0%, #ffd4d4 100%);
    color: #a52a2a;
    border: 2px solid #ffb3b3;
}

/* Footer */
footer {
    background: linear-gradient(135deg, var(--text-dark) 0%, #0a0a0a 100%);
    padding: var(--spacing-2xl) 0;
    text-align: center;
    color: var(--bg-white);
    border-top: 4px solid var(--accent-teal);
}

/* Language Content */
.lang-content {
    display: none;
}

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

/* Mobile Responsive */
@media (max-width: 768px) {
    :root {
        --font-size-5xl: 36px;
        --font-size-4xl: 28px;
        --font-size-3xl: 24px;
        --font-size-2xl: 20px;
        --spacing-3xl: 48px;
        --spacing-2xl: 32px;
    }

    .services-grid,
    .why-grid {
        grid-template-columns: 1fr;
    }

    .hero-stats {
        grid-template-columns: 1fr;
    }

    .main-nav {
        order: 3;
        width: 100%;
        justify-content: center;
        gap: var(--spacing-sm);
        padding-top: var(--spacing-sm);
        border-top: 1px solid var(--border-color);
    }

    .nav-link {
        font-size: var(--font-size-sm);
        padding: var(--spacing-xs) var(--spacing-md);
    }

    /* Минимизированный header */
    header {
        padding: var(--spacing-xs) 0;
        min-height: 48px;
        transition: all 0.3s ease;
    }

    .header-content {
        flex-direction: row;
        justify-content: space-between;
        align-items: center;
        gap: var(--spacing-sm);
    }

    .logo-section {
        text-align: left;
        min-width: auto;
    }

    .logo {
        font-size: var(--font-size-xl);
        margin-bottom: 0;
    }

    .tagline {
        display: none;
    }

    .language-switcher {
        justify-content: flex-end;
        gap: 4px;
        padding: 4px 8px;
        border-radius: var(--radius-sm);
        background: rgba(255,255,255,0.9);
        backdrop-filter: blur(4px);
        border: 1px solid var(--border-color);
    }

    .lang-btn {
        padding: 6px 10px;
        font-size: var(--font-size-xs);
        font-weight: 700;
        min-width: 40px;
    }

    .lang-btn.active {
        font-size: var(--font-size-sm);
    }

    header.scrolled {
        padding: 4px 0;
        min-height: 44px;
        background: rgba(255,255,255,0.97);
        backdrop-filter: blur(12px);
        box-shadow: var(--shadow-sm);
    }

    header.scrolled .logo {
        font-size: 18px;
    }
}

/* Тёмный режим по времени суток */
body.night {
    background: #0f172a;
    color: #e2e8f0;
}

body.night .hero {
    background: linear-gradient(135deg, #1e293b 0%, #0f172a 100%);
}

body.night header {
    background: rgba(15, 23, 42, 0.95);
    backdrop-filter: blur(10px);
    border-bottom-color: #334155;
}

body.night .nav-link {
    color: #e2e8f0;
}

body.night .nav-link:hover {
    color: #60a5fa;
    background: rgba(96, 165, 250, 0.1);
}

body.night .section-alt {
    background: #1e293b;
}

body.night .service-card,
body.night .why-item,
body.night .contact-form,
body.night .contact-info,
body.night .how-i-work,
body.night .stat-item {
    background: #1e293b;
    border-color: #334155;
}

body.night .tagline,
body.night .hero p,
body.night .section-subtitle,
body.night .service-card p,
body.night .why-item p,
body.night .how-i-work p,
body.night .stat-label {
    color: #cbd5e1;
}

body.night .primary-cta,
body.night .submit-btn {
    background: linear-gradient(135deg, #3b82f6 0%, #1d4ed8 100%);
}

body.night .logo {
    background: linear-gradient(135deg, #60a5fa 0%, #34d399 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

body.night .form-group input,
body.night .form-group textarea {
    background: #0f172a;
    border-color: #334155;
    color: #e2e8f0;
}

body.night .form-group input::placeholder,
body.night .form-group textarea::placeholder {
    color: #64748b;
}

body.night .form-group input:focus,
body.night .form-group textarea:focus {
    background: #1e293b;
    border-color: #60a5fa;
}

body.night .form-group label {
    color: #e2e8f0;
}

body.night .section-title,
body.night .service-card h3,
body.night .why-item h3,
body.night .how-i-work h3,
body.night .contact-form h3,
body.night .contact-info-item strong {
    color: #60a5fa;
}

/* Лёгкое свечение заголовков только ночью */
body.night h1,
body.night h2,
body.night h3,
body.night strong {
    text-shadow: 
        0 0 8px rgba(96, 165, 250, 0.6),
        0 0 16px rgba(96, 165, 250, 0.4),
        0 0 24px rgba(96, 165, 250, 0.2);
    color: #ffffff;
}

/* Днём свечения нет */
h1, h2, h3, strong {
    text-shadow: none;
}

/* Плавные переходы */
body, .hero, header, .service-card, .why-item, .contact-form, .contact-info, .section-alt, .primary-cta, .submit-btn, .stat-item, .tagline, .section-subtitle, .service-card p, .why-item p, .stat-label, h1, h2, h3, strong, .form-group label {
    transition: background 1s ease, color 1s ease, border-color 1s ease, text-shadow 1s ease;
}