/* Viet Web LLC - Main Stylesheet - Dark Mode */

/* ============================================
   CSS Variables & Reset
   ============================================ */
:root {
    /* Dark mode colors */
    --color-bg-primary: #0a0a0b;
    --color-bg-secondary: #111113;
    --color-bg-tertiary: #18181b;
    --color-bg-card: #1c1c1f;
    --color-bg-elevated: #232326;

    /* Accent colors - vibrant gradient */
    --color-accent-primary: #6366f1;
    --color-accent-secondary: #8b5cf6;
    --color-accent-tertiary: #a855f7;
    --color-accent-cyan: #22d3ee;
    --color-accent-emerald: #10b981;

    /* Text colors */
    --color-text-primary: #fafafa;
    --color-text-secondary: #a1a1aa;
    --color-text-tertiary: #71717a;
    --color-text-muted: #52525b;

    /* Border colors */
    --color-border: #27272a;
    --color-border-light: #3f3f46;

    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #6366f1 0%, #8b5cf6 50%, #a855f7 100%);
    --gradient-accent: linear-gradient(135deg, #22d3ee 0%, #6366f1 100%);
    --gradient-glow: radial-gradient(ellipse at center, rgba(99, 102, 241, 0.15) 0%, transparent 70%);

    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;

    /* Layout */
    --max-width: 1200px;
    --header-height: 80px;

    /* Effects */
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 40px rgba(99, 102, 241, 0.3);
}

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    font-size: 1rem;
    line-height: 1.7;
    color: var(--color-text-primary);
    background-color: var(--color-bg-primary);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

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

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

ul {
    list-style: none;
}

/* ============================================
   Typography
   ============================================ */
h1, h2, h3, h4, h5, h6 {
    color: var(--color-text-primary);
    line-height: 1.2;
    margin-bottom: 1rem;
    font-weight: 700;
    letter-spacing: -0.02em;
}

h1 {
    font-size: 3.5rem;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

h2 {
    font-size: 2.5rem;
}

h3 {
    font-size: 1.5rem;
}

h4 {
    font-size: 1.25rem;
}

p {
    margin-bottom: 1rem;
    color: var(--color-text-secondary);
}

/* ============================================
   Layout
   ============================================ */
.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 1.5rem;
}

.section {
    padding: 6rem 0;
    position: relative;
}

.section-alt {
    background-color: var(--color-bg-secondary);
}

main {
    flex: 1;
}

/* ============================================
   Header & Navigation
   ============================================ */
header {
    background-color: rgba(10, 10, 11, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 0;
    z-index: 1000;
    height: var(--header-height);
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 100%;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-decoration: none;
    letter-spacing: -0.02em;
}

.logo:hover {
    background: var(--gradient-accent);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.logo img {
    height: 56px;
    width: auto;
}

nav ul {
    display: flex;
    gap: 2.5rem;
    align-items: center;
}

nav a {
    color: var(--color-text-secondary);
    font-weight: 500;
    font-size: 0.95rem;
    padding: 0.5rem 0;
    position: relative;
    transition: var(--transition);
}

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

nav a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient-primary);
    transition: var(--transition);
    border-radius: 2px;
}

nav a:hover::after,
nav a.active::after {
    width: 100%;
}

/* Mobile Navigation */
.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: 0.5rem;
    background: none;
    border: none;
}

.nav-toggle span {
    width: 24px;
    height: 2px;
    background-color: var(--color-text-primary);
    border-radius: 2px;
    transition: var(--transition);
}

/* ============================================
   Hero Section
   ============================================ */
.hero {
    background: var(--color-bg-primary);
    padding: 8rem 0;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 150%;
    height: 100%;
    background: var(--gradient-glow);
    pointer-events: none;
}

.hero-content {
    position: relative;
    z-index: 1;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: 100px;
    font-size: 0.875rem;
    color: var(--color-text-secondary);
    margin-bottom: 2rem;
}

.hero-badge-dot {
    width: 8px;
    height: 8px;
    background: var(--color-accent-emerald);
    border-radius: 50%;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

.hero h1 {
    font-size: 4rem;
    margin-bottom: 1.5rem;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.hero p {
    font-size: 1.25rem;
    max-width: 600px;
    margin: 0 auto 2.5rem;
    color: var(--color-text-secondary);
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* ============================================
   Buttons
   ============================================ */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.875rem 2rem;
    font-size: 1rem;
    font-weight: 600;
    text-align: center;
    border-radius: 12px;
    border: none;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: var(--shadow-glow);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 0 60px rgba(99, 102, 241, 0.4);
    color: white;
}

.btn-secondary {
    background: var(--color-bg-card);
    color: var(--color-text-primary);
    border: 1px solid var(--color-border);
}

.btn-secondary:hover {
    background: var(--color-bg-elevated);
    border-color: var(--color-border-light);
    color: var(--color-text-primary);
}

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

.btn-outline:hover {
    background: var(--color-bg-card);
    border-color: var(--color-accent-primary);
    color: var(--color-text-primary);
}

/* ============================================
   Stats Section
   ============================================ */
.stats {
    padding: 4rem 0;
    border-top: 1px solid var(--color-border);
    border-bottom: 1px solid var(--color-border);
    background: var(--color-bg-secondary);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 2rem;
    text-align: center;
}

.stat-item h3 {
    font-size: 3rem;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 0.5rem;
}

.stat-item p {
    color: var(--color-text-tertiary);
    font-size: 0.95rem;
    margin: 0;
}

/* ============================================
   Features / Services Section
   ============================================ */
.features {
    padding: 6rem 0;
}

.section-header {
    text-align: center;
    margin-bottom: 4rem;
}

.section-header h2 {
    margin-bottom: 1rem;
}

.section-header p {
    max-width: 600px;
    margin: 0 auto;
    color: var(--color-text-secondary);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 1.5rem;
}

.feature-card {
    background: var(--color-bg-card);
    padding: 2rem;
    border-radius: 16px;
    border: 1px solid var(--color-border);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.feature-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--gradient-primary);
    opacity: 0;
    transition: var(--transition);
}

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

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

.feature-icon {
    width: 56px;
    height: 56px;
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.1) 0%, rgba(139, 92, 246, 0.1) 100%);
    border: 1px solid rgba(99, 102, 241, 0.2);
    border-radius: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1.5rem;
    color: var(--color-accent-primary);
}

.feature-card h3 {
    margin-bottom: 0.75rem;
    font-size: 1.25rem;
}

.feature-card p {
    color: var(--color-text-secondary);
    margin-bottom: 0;
    line-height: 1.6;
}

/* ============================================
   Process Section
   ============================================ */
.process-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 2rem;
    position: relative;
}

.process-grid::before {
    content: '';
    position: absolute;
    top: 40px;
    left: 10%;
    right: 10%;
    height: 2px;
    background: var(--color-border);
}

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

.process-number {
    width: 80px;
    height: 80px;
    background: var(--color-bg-card);
    border: 2px solid var(--color-border);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.5rem;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-accent-primary);
    position: relative;
    z-index: 1;
}

.process-step:hover .process-number {
    border-color: var(--color-accent-primary);
    box-shadow: var(--shadow-glow);
}

.process-step h3 {
    font-size: 1.125rem;
    margin-bottom: 0.5rem;
}

.process-step p {
    font-size: 0.95rem;
    color: var(--color-text-tertiary);
    margin: 0;
}

/* ============================================
   About / Content Sections
   ============================================ */
.about-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.about-text h2 {
    margin-bottom: 1.5rem;
}

.about-text p {
    color: var(--color-text-secondary);
}

.about-image {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: 20px;
    height: 400px;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
}

.about-image::before {
    content: '';
    position: absolute;
    inset: 0;
    background: var(--gradient-glow);
    opacity: 0.5;
}

/* Company Info Card */
.info-card {
    background: var(--color-bg-card);
    padding: 2rem;
    border-radius: 16px;
    border: 1px solid var(--color-border);
    margin-top: 2rem;
}

.info-card h3 {
    color: var(--color-text-primary);
    margin-bottom: 1rem;
    font-size: 1.25rem;
}

.info-card p {
    color: var(--color-text-secondary);
    margin-bottom: 0.5rem;
}

/* ============================================
   Technologies Section
   ============================================ */
.tech-grid {
    display: grid;
    grid-template-columns: repeat(6, 1fr);
    gap: 1.5rem;
}

.tech-item {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: 12px;
    padding: 1.5rem;
    text-align: center;
    transition: var(--transition);
}

.tech-item:hover {
    border-color: var(--color-border-light);
    transform: translateY(-2px);
}

.tech-item svg {
    margin-bottom: 0.75rem;
    color: var(--color-text-secondary);
}

.tech-item p {
    margin: 0;
    font-size: 0.875rem;
    color: var(--color-text-secondary);
}

/* ============================================
   CTA Section
   ============================================ */
.cta-section {
    padding: 6rem 0;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.cta-section::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 200%;
    height: 200%;
    background: var(--gradient-glow);
    pointer-events: none;
}

.cta-content {
    position: relative;
    z-index: 1;
    max-width: 600px;
    margin: 0 auto;
}

.cta-content h2 {
    margin-bottom: 1rem;
}

.cta-content p {
    margin-bottom: 2rem;
}

/* ============================================
   Contact Section
   ============================================ */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
}

.contact-info h2 {
    margin-bottom: 1.5rem;
}

.contact-details {
    margin-top: 2rem;
}

.contact-item {
    display: flex;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.contact-item-icon {
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.1) 0%, rgba(139, 92, 246, 0.1) 100%);
    border: 1px solid rgba(99, 102, 241, 0.2);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    color: var(--color-accent-primary);
}

.contact-item-content h4 {
    margin-bottom: 0.25rem;
    font-size: 1rem;
    color: var(--color-text-primary);
}

.contact-item-content p {
    color: var(--color-text-secondary);
    margin-bottom: 0;
}

/* Contact Form */
.contact-form {
    background: var(--color-bg-card);
    padding: 2.5rem;
    border-radius: 20px;
    border: 1px solid var(--color-border);
}

.contact-form h3 {
    margin-bottom: 1.5rem;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--color-text-primary);
    font-size: 0.95rem;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.875rem 1rem;
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: 10px;
    font-family: inherit;
    font-size: 1rem;
    color: var(--color-text-primary);
    transition: var(--transition);
}

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

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--color-accent-primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

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

/* ============================================
   Legal Pages (Privacy Policy, Terms)
   ============================================ */
.legal-content {
    background: var(--color-bg-card);
    padding: 3rem;
    border-radius: 20px;
    border: 1px solid var(--color-border);
    max-width: 900px;
    margin: 0 auto;
}

.legal-content h1 {
    margin-bottom: 0.5rem;
    font-size: 2.5rem;
}

.legal-content .last-updated {
    color: var(--color-text-tertiary);
    font-size: 0.875rem;
    margin-bottom: 2rem;
}

.legal-content h2 {
    font-size: 1.5rem;
    margin-top: 2.5rem;
    margin-bottom: 1rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--color-border);
    background: none;
    -webkit-text-fill-color: var(--color-text-primary);
}

.legal-content h2:first-of-type {
    border-top: none;
    padding-top: 0;
}

.legal-content h3 {
    font-size: 1.125rem;
    margin-top: 1.5rem;
    margin-bottom: 0.75rem;
}

.legal-content p {
    color: var(--color-text-secondary);
}

.legal-content ul,
.legal-content ol {
    margin-left: 1.5rem;
    margin-bottom: 1rem;
    color: var(--color-text-secondary);
}

.legal-content li {
    margin-bottom: 0.5rem;
    list-style: disc;
}

.legal-content ol li {
    list-style: decimal;
}

/* ============================================
   Footer
   ============================================ */
footer {
    background: var(--color-bg-secondary);
    border-top: 1px solid var(--color-border);
    padding: 4rem 0 2rem;
    margin-top: auto;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 3rem;
    margin-bottom: 3rem;
}

.footer-brand {
    max-width: 300px;
}

.footer-brand .logo {
    margin-bottom: 1rem;
}

.footer-brand p {
    font-size: 0.9rem;
    line-height: 1.7;
    color: var(--color-text-tertiary);
}

.footer-section h4 {
    color: var(--color-text-primary);
    font-size: 0.875rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 1.25rem;
}

.footer-section ul li {
    margin-bottom: 0.75rem;
}

.footer-section a {
    color: var(--color-text-tertiary);
    font-size: 0.9rem;
    transition: var(--transition);
}

.footer-section a:hover {
    color: var(--color-text-primary);
}

.footer-section li:not(:has(a)) {
    color: var(--color-text-tertiary);
    font-size: 0.9rem;
}

.footer-bottom {
    padding-top: 2rem;
    border-top: 1px solid var(--color-border);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.footer-bottom p {
    font-size: 0.875rem;
    color: var(--color-text-tertiary);
    margin-bottom: 0;
}

.footer-legal {
    display: flex;
    gap: 2rem;
}

.footer-legal a {
    color: var(--color-text-tertiary);
    font-size: 0.875rem;
}

/* ============================================
   Page Headers
   ============================================ */
.page-header {
    background: var(--color-bg-secondary);
    padding: 5rem 0;
    text-align: center;
    border-bottom: 1px solid var(--color-border);
    position: relative;
    overflow: hidden;
}

.page-header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 150%;
    height: 100%;
    background: var(--gradient-glow);
    pointer-events: none;
}

.page-header h1 {
    position: relative;
    z-index: 1;
    margin-bottom: 0.75rem;
    font-size: 3rem;
}

.page-header p {
    position: relative;
    z-index: 1;
    color: var(--color-text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

/* ============================================
   Utility Classes
   ============================================ */
.text-center {
    text-align: center;
}

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

.text-gradient {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }

/* ============================================
   Responsive Design
   ============================================ */
@media (max-width: 1024px) {
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .process-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .process-grid::before {
        display: none;
    }

    .tech-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

@media (max-width: 992px) {
    .about-content,
    .contact-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .about-image {
        height: 300px;
        order: -1;
    }

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

@media (max-width: 768px) {
    h1, .hero h1 {
        font-size: 2.5rem;
    }

    h2 {
        font-size: 2rem;
    }

    .hero {
        padding: 5rem 0;
    }

    .hero p {
        font-size: 1.1rem;
    }

    .section {
        padding: 4rem 0;
    }

    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 1.5rem;
    }

    .stat-item h3 {
        font-size: 2rem;
    }

    .process-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .tech-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .nav-toggle {
        display: flex;
    }

    nav {
        position: absolute;
        top: var(--header-height);
        left: 0;
        right: 0;
        background: rgba(10, 10, 11, 0.98);
        backdrop-filter: blur(20px);
        -webkit-backdrop-filter: blur(20px);
        border-bottom: 1px solid var(--color-border);
        padding: 1rem 0;
        display: none;
    }

    nav.active {
        display: block;
    }

    nav ul {
        flex-direction: column;
        gap: 0;
        padding: 0 1.5rem;
    }

    nav ul li {
        border-bottom: 1px solid var(--color-border);
    }

    nav ul li:last-child {
        border-bottom: none;
    }

    nav a {
        display: block;
        padding: 1rem 0;
    }

    .footer-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .footer-brand {
        max-width: 100%;
    }

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

    .legal-content {
        padding: 2rem 1.5rem;
    }

    .page-header h1 {
        font-size: 2.25rem;
    }
}

@media (max-width: 480px) {
    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }

    .btn {
        width: 100%;
        max-width: 280px;
    }

    .contact-form {
        padding: 1.5rem;
    }

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

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

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