/* ===== HUYHOANGSOFTWARE2025 - MAIN CSS ===== */
/* Inspired by cnv.vn - Modern Technology Company Design */

/* ===== RESET & BASE ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* --- DARK THEME PALETTE --- */
    /* Accent Colors */
    --primary-color: #3b82f6; /* Electric Blue for accents */
    --primary-dark: #2563eb;
    --primary-light: #60a5fa;
    --secondary-color: #06b6d4; /* Vibrant Cyan for secondary accents */

    /* Background Colors */
    --bg-primary: #0f172a; /* Deep Navy - Main BG */
    --bg-secondary: #1e293b; /* Lighter Navy - Card BG */
    --bg-tertiary: #334155; /* Slate Gray - Hover/Borders */

    /* Text Colors */
    --text-primary: #f8fafc; /* Almost White - Headings */
    --text-secondary: #cbd5e1; /* Light Slate - Paragraphs */
    --text-light: #94a3b8; /* Lighter Slate - Meta text */

    /* Border & Shadows */
    --border-color: #334155;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.2);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.3);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.3);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.3);
    --shadow-glow: 0 0 20px rgba(59, 130, 246, 0.2);
    
    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-heading: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    
    /* Spacing & Layout */
    --container-max-width: 1400px;
    --container-large-width: 90%;
    --section-padding: 80px 0;
    --section-padding-large: 120px 0;
    --border-radius: 12px;
    --border-radius-lg: 20px;
    
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
}

body {
    font-family: var(--font-primary);
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-secondary);
    background-color: var(--bg-primary);
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}
.contact-item {
    margin-bottom: 5px !important;
}
/* ===== TYPOGRAPHY ===== */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

h1 { font-size: 3.5rem; }
h2 { font-size: 2.5rem; }
h3 { font-size: 2rem; }
h4 { font-size: 1.5rem; }
h5 { font-size: 1.25rem; }
h6 { font-size: 1rem; }

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

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

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

/* ===== LAYOUT ===== */
.container {
    max-width: var(--container-max-width);
    width: var(--container-large-width);
    margin: 0 auto;
    padding: 0 20px;
}

/* Large Screen Optimization */
@media (min-width: 1400px) {
    .container {
        max-width: 90vw;
        width: 90%;
    }
    
    .section {
        padding: var(--section-padding-large);
    }
    
    .hero h1 {
        font-size: 5rem;
    }
    
    .section-title h2 {
        font-size: 3.5rem;
    }
}

@media (min-width: 1920px) {
    .container {
        max-width: 85vw;
        width: 85%;
    }
    
    .hero h1 {
        font-size: 6rem;
    }
}

.section {
    padding: var(--section-padding);
}

.row {
    display: flex;
    flex-wrap: wrap;
    margin: 0 -15px;
}

.col {
    padding: 0 15px;
}

.col-12 { flex: 0 0 100%; }
.col-6 { flex: 0 0 50%; }
.col-4 { flex: 0 0 33.333333%; }
.col-3 { flex: 0 0 25%; }

/* ===== BUTTONS ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 24px;
    font-size: 16px;
    font-weight: 600;
    text-decoration: none;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition-normal);
    position: relative;
    overflow: hidden;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    box-shadow: var(--shadow-glow);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 0 30px rgba(59, 130, 246, 0.4);
    color: white;
}

.btn-secondary {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 2px solid var(--border-color);
}

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

.btn-lg {
    padding: 16px 32px;
    font-size: 18px;
}

.btn-sm {
    padding: 8px 16px;
    font-size: 14px;
}

/* ===== HEADER ===== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(15, 23, 42, 0.85); /* --bg-primary with alpha */
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: var(--transition-normal);
}

.header.scrolled {
    background: rgba(15, 23, 42, 0.95);
    box-shadow: var(--shadow-md);
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 15px 0;
}

.logo {
    display: flex;
    align-items: center;
    font-size: 24px;
    font-weight: 700;
    color: var(--text-primary);
}

.logo img {
    height: 40px;
    margin-right: 10px;
    filter: brightness(110);
}

.nav {
    display: flex;
    align-items: center;
    list-style: none;
}

.nav-item {
    margin: 0 20px;
}

.nav-link {
    font-weight: 500;
    color: var(--text-secondary);
    position: relative;
    transition: var(--transition-fast);
}

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transition: var(--transition-fast);
}

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

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
    padding: 5px;
}

.mobile-menu-toggle span {
    width: 25px;
    height: 3px;
    background: var(--text-primary);
    margin: 3px 0;
    transition: var(--transition-fast);
}

/* ===== HERO SECTION ===== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    background: var(--bg-primary);
    color: var(--text-primary);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1000 1000"><defs><radialGradient id="a" cx="50%" cy="50%"><stop offset="0%" stop-color="rgba(59, 130, 246, 0.1)"/><stop offset="100%" stop-color="rgba(59, 130, 246, 0)"/></radialGradient></defs><circle cx="200" cy="200" r="100" fill="url(%23a)"/><circle cx="800" cy="300" r="150" fill="url(%23a)"/><circle cx="400" cy="700" r="120" fill="url(%23a)"/></svg>');
    opacity: 0.2;
}

.hero-content {
    position: relative;
    z-index: 2;
    text-align: center;
}

.hero h1 {
    font-size: 4rem;
    margin-bottom: 1.5rem;
    animation: fadeInUp 1s ease;
}

.hero p {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    color: var(--text-secondary);
    animation: fadeInUp 1s ease 0.2s both;
}

.hero-buttons {
    animation: fadeInUp 1s ease 0.4s both;
}

.hero-buttons .btn {
    margin: 0 10px;
}

/* ===== FEATURES SECTION ===== */
.features {
    background: var(--bg-primary);
}

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

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

.section-title p {
    font-size: 1.125rem;
    max-width: 600px;
    margin: 0 auto;
    color: var(--text-secondary);
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.feature-card {
    background: var(--bg-secondary);
    padding: 2rem;
    border-radius: var(--border-radius-lg);
    box-shadow: none;
    border: 1px solid var(--border-color);
    transition: var(--transition-normal);
    text-align: center;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-glow);
    border-color: var(--primary-color);
}

.feature-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 1.5rem;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    color: white;
}

.feature-card h3 {
    margin-bottom: 1rem;
    color: var(--text-primary);
}

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

/* ===== STATS SECTION ===== */
.stats {
    background: var(--bg-secondary);
    color: var(--text-primary);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    text-align: center;
}

.stat-item h3 {
    font-size: 3rem;
    color: var(--primary-light);
    margin-bottom: 0.5rem;
}

.stat-item p {
    color: var(--text-secondary);
    font-size: 1.125rem;
}

/* ===== PRICING SECTION ===== */
.pricing-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.pricing-card {
    background: var(--bg-secondary);
    border-radius: var(--border-radius-lg);
    padding: 2rem;
    border: 1px solid var(--border-color);
    transition: var(--transition-normal);
    position: relative;
    text-align: center;
}

.pricing-card.featured {
    transform: scale(1.05);
    border: 2px solid var(--primary-color);
    box-shadow: var(--shadow-glow);
}

.pricing-card.featured::before {
    content: 'Phổ biến nhất';
    position: absolute;
    top: -15px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--primary-color);
    color: white;
    padding: 8px 20px;
    border-radius: 20px;
    font-size: 14px;
    font-weight: 600;
}

.pricing-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-light);
}

.pricing-card.featured:hover {
    transform: scale(1.05) translateY(-5px);
}

.pricing-header h3 {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
}

.pricing-price {
    font-size: 3rem;
    font-weight: 700;
    color: var(--primary-light);
    margin: 1rem 0;
}

.pricing-price span {
    font-size: 1rem;
    color: var(--text-secondary);
}

.pricing-features {
    list-style: none;
    margin: 2rem 0;
}

.pricing-features li {
    padding: 0.5rem 0;
    color: var(--text-secondary);
}

.pricing-features li::before {
    content: '✓';
    color: var(--secondary-color);
    font-weight: bold;
    margin-right: 10px;
}

/* ===== FOOTER ===== */
.footer {
    background: var(--bg-primary);
    border-top: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: 4rem 0 2rem;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h4 {
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.footer-section p,
.footer-section a {
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
    display: block;
}

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

.social-links {
    display: flex;
    gap: 1rem;
    margin-top: 1rem;
}

.social-links a {
    width: 40px;
    height: 40px;
    background: var(--bg-secondary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-secondary);
    transition: var(--transition-fast);
}

.social-links a:hover {
    background: var(--primary-color);
    color: white;
    transform: translateY(-2px);
}

.footer-bottom {
    border-top: 1px solid var(--border-color);
    padding-top: 2rem;
    text-align: center;
    color: var(--text-light);
}

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

@keyframes fadeInLeft {
    from {
        opacity: 0;
        transform: translateX(-30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes fadeInRight {
    from {
        opacity: 0;
        transform: translateX(30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.animate-on-scroll {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.6s ease;
}

.animate-on-scroll.animated {
    opacity: 1;
    transform: translateY(0);
}

/* ===== UTILITIES ===== */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }
.mb-5 { margin-bottom: 3rem; }

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }
.mt-5 { margin-top: 3rem; }

.d-none { display: none; }
.d-block { display: block; }
.d-flex { display: flex; }
.d-grid { display: grid; }

.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.align-center { align-items: center; }

/* ==== GLOBAL ELEMENTS (Dark Polishing) ==== */
input, textarea, select {
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    border-radius: var(--border-radius);
    padding: 10px 12px;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

input::placeholder, textarea::placeholder {
    color: var(--text-light);
}

input:focus, textarea:focus, select:focus {
    outline: none;
    border-color: var(--primary-light);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.2);
}

.card, .box, .panel {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-sm);
}

hr {
    border-color: var(--border-color);
    opacity: .3;
}

/* Accordion (FAQ) */
.accordion { border: 0; }
.accordion-item {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-lg);
    overflow: hidden;
}
.accordion + .accordion, .accordion-item + .accordion-item { margin-top: 12px; }
.accordion-header { background: transparent; }
.accordion-button {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 0;
    padding: 18px 20px;
}
.accordion-button:not(.collapsed) {
    color: var(--text-primary);
    background: var(--bg-secondary);
    box-shadow: inset 0 -1px 0 var(--border-color);
}
.accordion-button:focus { box-shadow: 0 0 0 3px rgba(59,130,246,.2); border-color: var(--primary-light); }
.accordion-body { color: var(--text-secondary); background: var(--bg-secondary); }

/* Icon color unification */
.icon, .dropdown-icon, .service-icon i { color: var(--text-white); }

/* ===== RESPONSIVE ===== */
@media (max-width: 768px) {
    :root {
        --section-padding: 60px 0;
    }
    
    h1 { font-size: 2.5rem; }
    h2 { font-size: 2rem; }
    h3 { font-size: 1.5rem; }
    
    .hero h1 {
        font-size: 2.5rem;
    }
    
    .hero p {
        font-size: 1.125rem;
    }
    
    .nav {
        display: none;
    }
    
    .mobile-menu-toggle {
        display: flex;
    }
    
    .col-6,
    .col-4,
    .col-3 {
        flex: 0 0 100%;
    }
    
    .feature-grid,
    .pricing-grid {
        grid-template-columns: 1fr;
    }
    
    .pricing-card.featured {
        transform: none;
    }
    
    .pricing-card.featured:hover {
        transform: translateY(-5px);
    }
    
    .hero-buttons .btn {
        display: block;
        margin: 10px 0;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .hero h1 {
        font-size: 2rem;
    }
    
    .feature-card,
    .pricing-card {
        padding: 1.5rem;
    }
}