/**
 * МеталТруб — Industrial B2B Design
 * Fullscreen sections with parallax
 */

/* ==========================================================================
   Variables
   ========================================================================== */
:root {
    --bg: #0a0a0a;
    --surface: #141414;
    --text: #ffffff;
    --text-muted: rgba(255, 255, 255, 0.6);
    --accent: #f59e0b;
    --accent-hover: #fbbf24;
    --border: rgba(255, 255, 255, 0.1);
    --font: 'Inter', sans-serif;
    --transition: 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}

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

html {
    scroll-behavior: smooth;
    scroll-snap-type: y mandatory;
}

body {
    font-family: var(--font);
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    overflow-x: hidden;
}

a {
    text-decoration: none;
    color: inherit;
}

/* Back to Portfolio Button */
.back-to-portfolio {
    position: fixed;
    top: 100px;
    left: 24px;
    z-index: 1000;
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 16px;
    background: var(--accent);
    color: #000;
    font-size: 13px;
    font-weight: 600;
    border-radius: 100px;
    transition: all 0.3s ease;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

.back-to-portfolio:hover {
    background: var(--accent-hover);
    transform: translateX(-4px);
}

.back-to-portfolio svg {
    transition: transform 0.3s ease;
}

.back-to-portfolio:hover svg {
    transform: translateX(-3px);
}

button {
    cursor: pointer;
    border: none;
    background: none;
    font-family: inherit;
}

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

/* ==========================================================================
   Typography
   ========================================================================== */
h1 {
    font-size: clamp(64px, 10vw, 120px);
    font-weight: 700;
    line-height: 1.0;
    letter-spacing: -0.03em;
    text-transform: uppercase;
}

h2 {
    font-size: clamp(40px, 6vw, 72px);
    font-weight: 700;
    line-height: 1.1;
    letter-spacing: -0.02em;
}

/* ==========================================================================
   Buttons
   ========================================================================== */
.btn-primary {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 18px 40px;
    background: var(--accent);
    color: #000;
    font-size: 14px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    transition: all var(--transition);
}

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

.btn-primary.full {
    width: 100%;
}

.btn-outline {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 18px 0;
    background: transparent;
    color: var(--text);
    font-size: 14px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    border-bottom: 2px solid var(--text);
    transition: all var(--transition);
}

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

/* ==========================================================================
   Header
   ========================================================================== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    padding: 24px 48px;
    background: linear-gradient(to bottom, rgba(0, 0, 0, 0.8), transparent);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    max-width: 1600px;
    margin: 0 auto;
}

.logo {
    font-size: 18px;
    font-weight: 700;
    letter-spacing: 0.2em;
    text-transform: uppercase;
}

.nav {
    display: flex;
    gap: 32px;
}

.nav a {
    font-size: 13px;
    font-weight: 500;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    transition: color var(--transition);
}

.nav a:hover {
    color: var(--text);
}

.header-phone {
    font-size: 14px;
    font-weight: 600;
    color: var(--accent);
}

/* ==========================================================================
   Side Navigation
   ========================================================================== */
.side-nav {
    position: fixed;
    right: 32px;
    top: 50%;
    transform: translateY(-50%);
    z-index: 100;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.side-dot {
    width: 12px;
    height: 12px;
    border: 2px solid var(--text-muted);
    border-radius: 50%;
    transition: all var(--transition);
    position: relative;
}

.side-dot.active {
    background: var(--accent);
    border-color: var(--accent);
}

.side-dot span {
    position: absolute;
    right: 24px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 12px;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    white-space: nowrap;
    opacity: 0;
    transition: opacity var(--transition);
}

.side-dot:hover span {
    opacity: 1;
}

/* ==========================================================================
   Fullscreen Sections
   ========================================================================== */
.fullscreen-section {
    min-height: 100vh;
    position: relative;
    display: flex;
    align-items: center;
    scroll-snap-align: start;
    overflow: hidden;
}

.section-bg {
    position: absolute;
    inset: 0;
    background-size: cover;
    background-position: center;
    transition: transform 0.1s linear;
}

.section-bg::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(90deg, rgba(0, 0, 0, 0.85) 0%, rgba(0, 0, 0, 0.4) 50%, rgba(0, 0, 0, 0.6) 100%);
}

.section-content {
    position: relative;
    z-index: 2;
    width: 100%;
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 80px;
}

/* ==========================================================================
   Hero Section
   ========================================================================== */
.hero-section .section-content {
    padding-top: 100px;
}

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

.hero-desc {
    font-size: 18px;
    color: var(--text-muted);
    max-width: 500px;
    margin: 24px 0 40px;
    line-height: 1.8;
}

.hero-stats {
    display: flex;
    gap: 48px;
    margin-bottom: 48px;
}

.stat {
    display: flex;
    flex-direction: column;
}

.stat-value {
    font-size: 48px;
    font-weight: 700;
    color: var(--accent);
}

.stat-label {
    font-size: 13px;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

/* Scroll Indicator */
.scroll-indicator {
    position: absolute;
    bottom: 40px;
    left: 80px;
    display: flex;
    align-items: center;
    gap: 16px;
}

.scroll-indicator span {
    font-size: 12px;
    text-transform: uppercase;
    letter-spacing: 0.2em;
    color: var(--text-muted);
}

.scroll-line {
    width: 60px;
    height: 2px;
    background: var(--text-muted);
    position: relative;
    overflow: hidden;
}

.scroll-line::after {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    width: 30px;
    height: 100%;
    background: var(--accent);
    animation: scrollLine 2s ease-in-out infinite;
}

@keyframes scrollLine {
    0% {
        left: -30px;
    }

    100% {
        left: 60px;
    }
}

/* ==========================================================================
   Section Text
   ========================================================================== */
.section-text {
    max-width: 550px;
}

.section-text.align-right {
    margin-left: auto;
}

.section-number {
    display: block;
    font-size: 14px;
    font-weight: 600;
    color: var(--accent);
    margin-bottom: 8px;
}

.section-label {
    display: block;
    font-size: 12px;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.2em;
    color: var(--text-muted);
    margin-bottom: 16px;
}

.section-text h2 {
    margin-bottom: 24px;
}

.section-text>p {
    font-size: 16px;
    color: var(--text-muted);
    line-height: 1.8;
    margin-bottom: 32px;
}

.section-list {
    list-style: none;
    margin-bottom: 40px;
}

.section-list li {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 0;
    border-bottom: 1px solid var(--border);
    font-size: 15px;
}

.section-list li::before {
    content: '';
    width: 8px;
    height: 8px;
    background: var(--accent);
    border-radius: 50%;
}

/* ==========================================================================
   Contact Section
   ========================================================================== */
.contact-section .section-bg::after {
    background: linear-gradient(90deg, rgba(0, 0, 0, 0.9) 0%, rgba(0, 0, 0, 0.7) 100%);
}

.contact-wrapper {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 80px;
    align-items: center;
}

.contact-info h2 {
    margin-bottom: 20px;
}

.contact-info>p {
    color: var(--text-muted);
    margin-bottom: 40px;
}

.contact-details {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.contact-item {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.contact-label {
    font-size: 12px;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-muted);
}

.contact-value {
    font-size: 18px;
    font-weight: 500;
}

.contact-form {
    background: var(--surface);
    padding: 48px;
    border: 1px solid var(--border);
}

.form-group {
    margin-bottom: 20px;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 18px 20px;
    background: var(--bg);
    border: 1px solid var(--border);
    color: var(--text);
    font-size: 15px;
    outline: none;
    transition: border-color var(--transition);
}

.form-group input:focus,
.form-group textarea:focus {
    border-color: var(--accent);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: var(--text-muted);
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

/* ==========================================================================
   Footer
   ========================================================================== */
.footer {
    padding: 24px 48px;
    background: var(--bg);
    border-top: 1px solid var(--border);
}

.footer-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1600px;
    margin: 0 auto;
    font-size: 13px;
    color: var(--text-muted);
}

.footer .logo {
    font-size: 14px;
}

.footer a {
    color: var(--accent);
}

/* ==========================================================================
   Responsive
   ========================================================================== */
@media (max-width: 1024px) {
    .header {
        padding: 16px 24px;
    }

    .nav {
        display: none;
    }

    .side-nav {
        display: none;
    }

    .section-content {
        padding: 0 24px;
    }

    .scroll-indicator {
        left: 24px;
    }

    .hero-stats {
        flex-wrap: wrap;
        gap: 32px;
    }

    .contact-wrapper {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .section-text.align-right {
        margin-left: 0;
    }
}

@media (max-width: 768px) {
    html {
        scroll-snap-type: none;
    }

    .fullscreen-section {
        min-height: auto;
        padding: 120px 0 80px;
    }

    .hero-section {
        min-height: 100vh;
    }

    .stat-value {
        font-size: 36px;
    }

    .contact-form {
        padding: 24px;
    }

    .footer-inner {
        flex-direction: column;
        gap: 16px;
        text-align: center;
    }
}