:root {
    --primary: #0d6efd;
    --primary-dark: #0a58ca;
    --secondary: #f1f5f9;
    --accent: #0f172a;
    --text-main: #0b1120;
    --text-muted: #64748b;
    --white: #ffffff;
    --shadow-soft: 0 18px 45px rgba(15, 23, 42, 0.15);
    --radius-lg: 1.25rem;
    --transition: 0.3s ease;
}

*,
*::before,
*::after {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    background: #f8fafc;
    color: var(--text-main);
    line-height: 1.7;
}

/* Header / Nav */
header {
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    background: linear-gradient(to left, rgba(15, 23, 42, 0.95), rgba(15, 23, 42, 0.85));
    backdrop-filter: blur(10px);
    box-shadow: 0 4px 15px rgba(15, 23, 42, 0.35);
}

.nav-container {
    max-width: 1140px;
    margin: 0 auto;
    padding: 0.5rem 1.25rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
}

.logo-box {
    display: flex;
    align-items: center;
}

.logo-box img {
    max-height: 58px;
    display: block;
}

/* Nav */
nav ul {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    gap: 1rem;
}

nav a {
    color: #e5e7eb;
    text-decoration: none;
    font-size: 0.95rem;
    padding: 0.4rem 0.8rem;
    border-radius: 999px;
    transition: var(--transition);
}

nav a:hover {
    background: rgba(148, 163, 184, 0.25);
    color: #ffffff;
}

/* Hero */
.hero {
    position: relative;
    min-height: 90vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    color: var(--white);
    padding: 6rem 1.5rem 4rem;
    background-image:
        linear-gradient(to top, rgba(15, 23, 42, 0.93), rgba(15, 23, 42, 0.7)),
        url("https://via.placeholder.com/1600x900?text=Aluminum+%26+PVC+Factory");
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
}

.hero-overlay {
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at top, rgba(37, 99, 235, 0.4), transparent 60%);
}

.hero-content {
    position: relative;
    max-width: 800px;
    z-index: 1;
}

.hero h1 {
    font-size: clamp(2.1rem, 3vw + 1.1rem, 3.1rem);
    margin-bottom: 1rem;
}

.hero-subtitle {
    font-size: 1.05rem;
    margin-bottom: 2rem;
    color: #e2e8f0;
}

.hero-buttons {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 0.8rem;
    margin-bottom: 1.5rem;
}

.hero-meta {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 0.75rem;
    font-size: 0.9rem;
    color: #cbd5f5;
}

.hero-meta span {
    padding: 0.3rem 0.8rem;
    border-radius: 999px;
    border: 1px solid rgba(148, 163, 184, 0.6);
    background: rgba(15, 23, 42, 0.6);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.35rem;
    padding: 0.65rem 1.4rem;
    border-radius: 999px;
    border: 1px solid transparent;
    font-size: 0.95rem;
    cursor: pointer;
    text-decoration: none;
    transition: var(--transition);
    white-space: nowrap;
}

.btn.primary {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: var(--white);
    box-shadow: 0 12px 30px rgba(37, 99, 235, 0.45);
}

.btn.primary:hover {
    background: linear-gradient(135deg, var(--primary-dark), var(--primary));
    transform: translateY(-1px);
    box-shadow: 0 16px 34px rgba(37, 99, 235, 0.6);
}

.btn.secondary {
    background: transparent;
    color: #e5e7eb;
    border-color: rgba(148, 163, 184, 0.8);
}

.btn.secondary:hover {
    background: rgba(15, 23, 42, 0.8);
}

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

/* Sections */
.section {
    padding: 4.5rem 1.5rem;
}

.section:nth-of-type(odd) {
    background: #ffffff;
}

.section:nth-of-type(even) {
    background: #f8fafc;
}

.section-header {
    max-width: 720px;
    margin: 0 auto 2.5rem;
    text-align: center;
}

.section-header h2 {
    font-size: 1.8rem;
    margin-bottom: 0.5rem;
}

.section-header p {
    margin: 0;
    color: var(--text-muted);
}

/* Layout helpers */
.about-grid,
.contact-grid,
.quality-grid,
.cards-grid,
.gallery-grid {
    max-width: 1140px;
    margin: 0 auto;
}

/* About */
.about-grid {
    display: grid;
    grid-template-columns: minmax(0, 2fr) minmax(0, 1.4fr);
    gap: 2rem;
    align-items: start;
}

.about-text p {
    margin-top: 0;
    margin-bottom: 1rem;
}

.about-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.about-list li {
    position: relative;
    padding-right: 1.4rem;
    margin-bottom: 0.6rem;
    color: var(--text-muted);
}

.about-list li::before {
    content: "•";
    position: absolute;
    right: 0;
    color: var(--primary);
    font-weight: bold;
}

.about-box {
    background: radial-gradient(circle at top, #e0f2fe, #ffffff);
    border-radius: var(--radius-lg);
    padding: 1.6rem 1.4rem;
    box-shadow: var(--shadow-soft);
    border: 1px solid #dbeafe;
}

.about-box h3 {
    margin-top: 0;
    margin-bottom: 1rem;
    font-size: 1.1rem;
}

.about-box ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.about-box li {
    font-size: 0.95rem;
    margin-bottom: 0.4rem;
}

.about-box span {
    color: var(--text-muted);
    font-weight: 600;
}

/* Cards / Services */
.cards-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 1.4rem;
}

.card {
    background: #ffffff;
    border-radius: var(--radius-lg);
    padding: 1.4rem 1.3rem;
    box-shadow: 0 10px 25px rgba(15, 23, 42, 0.08);
    border: 1px solid #e2e8f0;
    transition: var(--transition);
}

.card h3 {
    margin-top: 0;
    margin-bottom: 0.6rem;
    font-size: 1.05rem;
}

.card p {
    margin: 0;
    color: var(--text-muted);
    font-size: 0.95rem;
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: 0 20px 40px rgba(15, 23, 42, 0.16);
    border-color: #bfdbfe;
}

/* Quality */
.quality-grid {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 1.25rem;
}

.quality-item {
    background: #0f172a;
    color: #e5e7eb;
    border-radius: var(--radius-lg);
    padding: 1.2rem 1.1rem;
    box-shadow: var(--shadow-soft);
}

.quality-item h3 {
    margin-top: 0;
    margin-bottom: 0.5rem;
    font-size: 1rem;
}

.quality-item p {
    margin: 0;
    font-size: 0.9rem;
    color: #cbd5f5;
}

/* Gallery */
.gallery-note {
    max-width: 1140px;
    margin: 0 auto 1.2rem;
    color: var(--text-muted);
    font-size: 0.9rem;
    text-align: center;
}

.gallery-grid {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 1rem;
}

.gallery-item {
    border-radius: 1rem;
    overflow: hidden;
    box-shadow: 0 12px 28px rgba(15, 23, 42, 0.18);
    border: 1px solid #e2e8f0;
}

.gallery-item img {
    width: 100%;
    height: 100%;
    display: block;
    object-fit: cover;
    transition: transform 0.35s ease;
}

.gallery-item:hover img {
    transform: scale(1.05);
}

/* Contact */
.contact-grid {
    display: grid;
    grid-template-columns: minmax(0, 1.2fr) minmax(0, 1.6fr);
    gap: 2rem;
    max-width: 1140px;
    margin: 0 auto 2.5rem;
}

.contact-info h3,
.contact-form-box h3 {
    margin-top: 0;
}

.contact-info ul {
    list-style: none;
    padding: 0;
    margin: 0 0 1.2rem;
}

.contact-info li {
    margin-bottom: 0.6rem;
    font-size: 0.95rem;
}

.contact-info span {
    font-weight: 600;
    color: var(--text-muted);
    margin-left: 0.25rem;
}

.contact-info a {
    color: var(--primary-dark);
    text-decoration: none;
}

.contact-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.6rem;
}

.contact-form-box {
    background: #ffffff;
    border-radius: var(--radius-lg);
    padding: 1.6rem 1.4rem;
    border: 1px solid #e2e8f0;
    box-shadow: var(--shadow-soft);
}

.contact-form .form-group {
    margin-bottom: 0.9rem;
}

.contact-form label {
    display: block;
    margin-bottom: 0.3rem;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-muted);
}

.contact-form input,
.contact-form textarea {
    width: 100%;
    padding: 0.55rem 0.7rem;
    border-radius: 0.6rem;
    border: 1px solid #cbd5e1;
    font-family: inherit;
    font-size: 0.95rem;
    transition: var(--transition);
}

.contact-form input:focus,
.contact-form textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 1px rgba(37, 99, 235, 0.25);
}

.map-box {
    max-width: 1140px;
    margin: 0 auto;
}

.map-box h3 {
    margin-top: 0;
    margin-bottom: 0.8rem;
}

.map-container {
    border-radius: 1.1rem;
    overflow: hidden;
    border: 1px solid #e2e8f0;
    box-shadow: var(--shadow-soft);
    background: #0f172a;
}

.map-container iframe {
    width: 100%;
    height: 320px;
    border: 0;
}

/* Footer */
.footer {
    text-align: center;
    padding: 1.4rem 1rem 2rem;
    background: #020617;
    color: #94a3b8;
    font-size: 0.9rem;
}

.footer .back-to-top {
    display: inline-block;
    margin-top: 0.5rem;
    color: #e5e7eb;
    text-decoration: none;
    font-size: 0.9rem;
}

.footer .back-to-top:hover {
    text-decoration: underline;
}

/* Fade-in animation */
.fade-in {
    opacity: 0;
    transform: translateY(10px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Responsive */
@media (max-width: 960px) {
    .cards-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
    .quality-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
    .gallery-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
    .about-grid,
    .contact-grid {
        grid-template-columns: minmax(0, 1fr);
    }
}

@media (max-width: 720px) {
    .nav-container {
        flex-direction: column;
        align-items: flex-start;
    }
    nav ul {
        flex-wrap: wrap;
        justify-content: flex-start;
    }
    .hero {
        background-attachment: scroll;
    }
}

@media (max-width: 480px) {
    .cards-grid,
    .quality-grid,
    .gallery-grid {
        grid-template-columns: minmax(0, 1fr);
    }
    nav a {
        font-size: 0.85rem;
    }
    .hero {
        padding-top: 6.5rem;
    }
}


/* Gallery tabs */
.gallery-tabs {
    max-width: 1140px;
    margin: 0 auto 1.5rem;
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    justify-content: center;
}

.gallery-tab {
    border: 1px solid #cbd5e1;
    background: #ffffff;
    padding: 0.4rem 1rem;
    border-radius: 999px;
    font-size: 0.9rem;
    cursor: pointer;
    transition: var(--transition);
}

.gallery-tab.active {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: #ffffff;
    border-color: transparent;
    box-shadow: 0 10px 25px rgba(37, 99, 235, 0.35);
}

.gallery-tab:hover:not(.active) {
    background: #e2e8f0;
}

.gallery-panels {
    max-width: 1140px;
    margin: 0 auto;
}

.gallery-panel {
    display: none;
}

.gallery-panel.active {
    display: block;
}

@media (max-width: 720px) {
    .gallery-tabs {
        justify-content: flex-start;
        overflow-x: auto;
    }
}