/* =============================================================
   it.byvto.ru — Modern Corporate Landing Page
   Сергей Мочалов / Техно-творчество в разработке
   ============================================================= */

/* --- CSS Variables (Dark Theme by default) -------------------- */
:root {
    /* Colors - Dark Theme */
    --bg-primary: #0a0e17;
    --bg-secondary: #111827;
    --bg-card: #1a1f2e;
    --bg-card-hover: #1f2937;
    --bg-glass: rgba(17, 24, 39, 0.7);

    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;

    --accent: #6366f1;
    --accent-light: #818cf8;
    --accent-glow: rgba(99, 102, 241, 0.3);
    --gradient-1: linear-gradient(135deg, #6366f1 0%, #8b5cf6 50%, #a855f7 100%);
    --gradient-2: linear-gradient(135deg, #06b6d4 0%, #3b82f6 100%);
    --gradient-hero: linear-gradient(135deg, #0f172a 0%, #1e1b4b 50%, #0f172a 100%);

    --border: rgba(255, 255, 255, 0.06);
    --border-light: rgba(255, 255, 255, 0.1);

    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;

    /* Typography */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

    /* Spacing */
    --container: 1200px;
    --radius-sm: 8px;
    --radius: 12px;
    --radius-lg: 20px;
    --radius-xl: 28px;

    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 20px 60px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 40px var(--accent-glow);

    /* Transitions */
    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Light Theme */
[data-theme="light"] {
    --bg-primary: #f8fafc;
    --bg-secondary: #ffffff;
    --bg-card: #ffffff;
    --bg-card-hover: #f1f5f9;
    --bg-glass: rgba(255, 255, 255, 0.8);

    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #94a3b8;

    --accent-glow: rgba(99, 102, 241, 0.15);
    --gradient-hero: linear-gradient(135deg, #eef2ff 0%, #faf5ff 50%, #ecfeff 100%);

    --border: rgba(0, 0, 0, 0.06);
    --border-light: rgba(0, 0, 0, 0.1);

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 20px 60px rgba(0, 0, 0, 0.12);
}

/* --- Reset & Base ---------------------------------------------- */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-sans);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.7;
    min-height: 100vh;
    transition: background var(--transition-slow), color var(--transition-slow);
}

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

a:hover {
    color: var(--accent);
}

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

/* --- Container ------------------------------------------------- */
.container {
    width: 100%;
    max-width: var(--container);
    margin: 0 auto;
    padding: 0 24px;
}

/* --- Typography ------------------------------------------------ */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.3;
}

h1 { font-size: clamp(2.5rem, 5vw, 4rem); }
h2 { font-size: clamp(1.8rem, 3.5vw, 2.5rem); }
h3 { font-size: 1.25rem; }

.section-title {
    text-align: center;
    margin-bottom: 60px;
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 3px;
    background: var(--gradient-1);
    margin: 16px auto 0;
    border-radius: 2px;
}

/* --- Header ---------------------------------------------------- */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    background: var(--bg-glass);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    transition: background var(--transition), border var(--transition);
}

.header__inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 72px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-weight: 700;
    font-size: 1.2rem;
    color: var(--text-primary);
    transition: opacity var(--transition);
}

.logo:hover {
    opacity: 0.8;
    color: var(--text-primary);
}

.logo__icon {
    font-size: 1.6rem;
}

.nav {
    display: flex;
    align-items: center;
    gap: 8px;
}

.nav__link {
    padding: 8px 16px;
    border-radius: 8px;
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 500;
    transition: all var(--transition);
}

.nav__link:hover {
    color: var(--text-primary);
    background: var(--bg-card-hover);
}

.header__actions {
    display: flex;
    align-items: center;
    gap: 8px;
}

/* --- Buttons --------------------------------------------------- */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 24px;
    border: none;
    border-radius: var(--radius);
    font-family: inherit;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition);
    text-decoration: none;
}

.btn--primary {
    background: var(--gradient-1);
    color: #fff;
    box-shadow: 0 4px 15px var(--accent-glow);
}

.btn--primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px var(--accent-glow);
    color: #fff;
}

.btn--lg {
    padding: 16px 36px;
    font-size: 1.1rem;
    border-radius: var(--radius-lg);
}

.btn--sm {
    padding: 8px 16px;
    font-size: 0.85rem;
}

.btn--outline {
    background: transparent;
    border: 1px solid var(--border-light);
    color: var(--text-primary);
}

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

.btn--icon {
    width: 40px;
    height: 40px;
    padding: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    cursor: pointer;
    font-size: 1rem;
    transition: all var(--transition);
}

.btn--icon:hover {
    background: var(--bg-card-hover);
    border-color: var(--border-light);
}

/* Theme toggle */
.theme-toggle .icon-sun,
.theme-toggle .icon-moon {
    transition: opacity var(--transition);
}

[data-theme="dark"] .icon-sun { display: none; }
[data-theme="dark"] .icon-moon { display: inline; }
[data-theme="light"] .icon-sun { display: inline; }
[data-theme="light"] .icon-moon { display: none; }

/* --- Hero Section ---------------------------------------------- */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: 72px;
    overflow: hidden;
}

.hero__bg {
    position: absolute;
    inset: 0;
    background: var(--gradient-hero);
    z-index: -1;
}

.hero__bg::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background:
        radial-gradient(ellipse at 20% 50%, rgba(99, 102, 241, 0.08) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 20%, rgba(6, 182, 212, 0.06) 0%, transparent 50%),
        radial-gradient(ellipse at 50% 80%, rgba(139, 92, 246, 0.06) 0%, transparent 50%);
    animation: bgFloat 20s ease-in-out infinite;
}

@keyframes bgFloat {
    0%, 100% { transform: translate(0, 0); }
    33% { transform: translate(1%, -1%); }
    66% { transform: translate(-1%, 1%); }
}

.hero__inner {
    position: relative;
    z-index: 1;
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
    padding: 80px 24px;
}

.hero__title {
    font-size: clamp(2.8rem, 6vw, 4.5rem);
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 24px;
    background: var(--gradient-1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero__subtitle {
    font-size: clamp(1.1rem, 2vw, 1.35rem);
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto 40px;
    line-height: 1.7;
}

.hero__cta {
    margin-top: 8px;
}

/* --- Tech Badge Row -------------------------------------------- */
.tech-strip {
    position: relative;
    z-index: 2;
    margin-top: -60px;
    padding: 0 24px 60px;
}

.tech-strip__inner {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 12px;
}

.tech-badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 8px 18px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 100px;
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-secondary);
    transition: all var(--transition);
}

.tech-badge:hover {
    border-color: var(--accent);
    color: var(--accent-light);
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.tech-badge__dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--accent);
}

/* --- Sections General ------------------------------------------ */
section {
    padding: 100px 0;
    position: relative;
}

/* --- About Section --------------------------------------------- */
.about {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
}

.about__card {
    max-width: 800px;
    margin: 0 auto;
    padding: 48px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-xl);
    position: relative;
    overflow: hidden;
}

.about__card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--gradient-1);
}

.about__text {
    font-size: 1.1rem;
    color: var(--text-secondary);
    line-height: 1.8;
}

/* --- Stats Row ------------------------------------------------- */
.stats {
    padding: 0 0 100px;
}

.stats__grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 24px;
    max-width: 900px;
    margin: 0 auto;
}

.stat-card {
    text-align: center;
    padding: 32px 24px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    transition: all var(--transition);
}

.stat-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--accent);
}

.stat-card__value {
    font-size: 2.5rem;
    font-weight: 800;
    background: var(--gradient-1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 8px;
}

.stat-card__label {
    font-size: 0.9rem;
    color: var(--text-muted);
    font-weight: 500;
}

/* --- Projects Section ------------------------------------------ */
.projects__grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 24px;
}

.project-card {
    display: flex;
    flex-direction: column;
    padding: 36px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    transition: all var(--transition-slow);
    position: relative;
    overflow: hidden;
    color: var(--text-primary);
    text-decoration: none;
}

.project-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--color, var(--gradient-1));
    opacity: 0;
    transition: opacity var(--transition);
}

.project-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
    border-color: var(--accent);
    color: var(--text-primary);
}

.project-card:hover::before {
    opacity: 1;
}

.project-card--soon {
    opacity: 0.6;
    cursor: default;
}

.project-card--soon:hover {
    transform: none;
    box-shadow: none;
    border-color: var(--border);
}

.project-card__icon-wrap {
    width: 56px;
    height: 56px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-secondary);
    border-radius: var(--radius);
    margin-bottom: 20px;
    border: 1px solid var(--border);
}

.project-card__icon {
    font-size: 1.6rem;
}

.project-card__content {
    flex: 1;
}

.project-card__name {
    font-size: 1.15rem;
    font-weight: 700;
    margin-bottom: 8px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.project-card__badge {
    display: inline-block;
    padding: 2px 10px;
    background: var(--bg-secondary);
    border: 1px solid var(--warning);
    border-radius: 100px;
    font-size: 0.7rem;
    font-weight: 600;
    color: var(--warning);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.project-card__subtitle {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 12px;
    line-height: 1.5;
}

.project-card__desc {
    font-size: 0.85rem;
    color: var(--text-muted);
    line-height: 1.6;
}

.project-card__arrow {
    margin-top: 20px;
    font-size: 1.2rem;
    color: var(--accent);
    transition: transform var(--transition);
}

.project-card:hover .project-card__arrow {
    transform: translateX(6px);
}

/* --- CTA Section ----------------------------------------------- */
.cta {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
}

.cta__card {
    max-width: 700px;
    margin: 0 auto;
    text-align: center;
    padding: 60px 40px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-xl);
    position: relative;
    overflow: hidden;
}

.cta__card::before {
    content: '';
    position: absolute;
    inset: 0;
    background: var(--gradient-1);
    opacity: 0.03;
}

.cta__title {
    font-size: clamp(1.5rem, 3vw, 2rem);
    margin-bottom: 16px;
}

.cta__text {
    font-size: 1.05rem;
    color: var(--text-secondary);
    margin-bottom: 32px;
}

/* --- Contact Section ------------------------------------------- */
.contact {
    padding: 80px 0;
}

.contact__grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 24px;
    max-width: 800px;
    margin: 0 auto;
}

.contact-card {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 24px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    transition: all var(--transition);
    color: var(--text-primary);
    text-decoration: none;
}

.contact-card:hover {
    border-color: var(--accent);
    transform: translateY(-2px);
    box-shadow: var(--shadow);
    color: var(--text-primary);
}

.contact-card__icon {
    font-size: 1.8rem;
}

.contact-card__label {
    font-size: 0.8rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 4px;
}

.contact-card__value {
    font-weight: 600;
    font-size: 1rem;
}

/* --- Footer ---------------------------------------------------- */
.footer {
    padding: 40px 0;
    border-top: 1px solid var(--border);
    background: var(--bg-secondary);
}

.footer__inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 16px;
}

.footer__text {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.footer__links {
    display: flex;
    gap: 20px;
}

.footer__link {
    font-size: 0.85rem;
    color: var(--text-muted);
    transition: color var(--transition);
}

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

/* --- Empty State ----------------------------------------------- */
.empty-state {
    grid-column: 1 / -1;
    text-align: center;
    padding: 60px 24px;
    color: var(--text-muted);
}

/* --- Section Divider ------------------------------------------- */
.section-divider {
    height: 1px;
    background: var(--border);
    margin: 0;
}

/* --- Animations ------------------------------------------------- */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.animate-in {
    animation: fadeInUp 0.6s ease-out forwards;
}

/* --- Scroll Reveal --------------------------------------------- */
[data-reveal] {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.6s ease-out;
}

[data-reveal].revealed {
    opacity: 1;
    transform: translateY(0);
}

/* --- Responsive ------------------------------------------------ */
@media (max-width: 768px) {
    .header__inner {
        height: 60px;
    }

    .nav {
        display: none;
    }

    .hero__inner {
        padding: 60px 16px;
    }

    section {
        padding: 60px 0;
    }

    .about__card {
        padding: 28px;
    }

    .projects__grid {
        grid-template-columns: 1fr;
    }

    .contact__grid {
        grid-template-columns: 1fr;
    }

    .footer__inner {
        flex-direction: column;
        text-align: center;
    }

    .tech-strip {
        margin-top: -40px;
        padding-bottom: 40px;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 16px;
    }

    .hero__title {
        font-size: 2.2rem;
    }

    .btn--lg {
        padding: 14px 28px;
        font-size: 1rem;
    }

    .stats__grid {
        grid-template-columns: 1fr 1fr;
    }
}