/* --- CONFIGURATION --- */
:root {
    /* Color Palette */
    --bg-color: #FAFAFA;
    /* Trắng hơi xám nhẹ (Off-white) dễ chịu hơn trắng tinh */
    --surface-color: #FFFFFF;
    /* Màu nền của Card */
    --text-primary: #111111;
    --text-secondary: #666666;
    --accent-color: #2563EB;
    /* Royal Blue */
    --border-color: #EAEAEA;

    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #2563EB 0%, #7C3AED 100%);
    /* Xanh sang Tím */

    /* Spacing & Radius */
    --radius-md: 12px;
    --radius-sm: 6px;

    /* Typography */
    --font-display: 'Space Grotesk', sans-serif;
    --font-body: 'Inter', sans-serif;
    --font-mono: 'JetBrains Mono', monospace;
}

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

body {
    background-color: var(--bg-color);
    color: var(--text-primary);
    font-family: var(--font-body);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

/* --- BACKGROUND PATTERN (CSS Only) --- */
.bg-grid {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: radial-gradient(#E5E5E5 1px, transparent 1px);
    background-size: 24px 24px;
    z-index: -1;
    opacity: 0.6;
}

/* --- LAYOUT --- */
.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 24px;
}

/* --- HEADER --- */
.site-header {
    background: rgba(250, 250, 250, 0.8);
    backdrop-filter: blur(10px);
    /* Hiệu ứng kính mờ */
    position: sticky;
    top: 0;
    z-index: 100;
    border-bottom: 1px solid var(--border-color);
}

.header-inner {
    height: 70px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 1.25rem;
    display: flex;
    align-items: center;
    gap: 8px;
}

.logo-mark {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    font-size: 1.5rem;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-secondary);
    margin: 0 16px;
    font-size: 0.95rem;
    font-weight: 500;
    transition: color 0.2s;
}

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

.btn-contact {
    text-decoration: none;
    background: var(--text-primary);
    color: white;
    padding: 8px 16px;
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    font-weight: 500;
    transition: transform 0.2s, opacity 0.2s;
}

.btn-contact:hover {
    transform: translateY(-1px);
    opacity: 0.9;
}

/* --- HERO SECTION --- */
.hero {
    padding: 100px 0 80px;
    text-align: center;
    max-width: 700px;
    margin: 0 auto;
}

.badge {
    display: inline-block;
    padding: 4px 12px;
    background: #EFF6FF;
    color: var(--accent-color);
    border-radius: 20px;
    font-family: var(--font-mono);
    font-size: 0.8rem;
    font-weight: 500;
    margin-bottom: 24px;
    border: 1px solid #DBEAFE;
}

.hero-title {
    font-family: var(--font-display);
    font-size: 3.5rem;
    line-height: 1.1;
    margin-bottom: 24px;
    letter-spacing: -0.02em;
}

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

.hero-desc {
    font-size: 1.15rem;
    color: var(--text-secondary);
}

/* --- SECTIONS & GRID --- */
.section {
    padding: 60px 0;
}

.section-title {
    font-family: var(--font-display);
    font-size: 1.5rem;
    margin-bottom: 32px;
    display: flex;
    align-items: center;
}

.section-title::after {
    content: "";
    flex: 1;
    height: 1px;
    background: var(--border-color);
    margin-left: 24px;
}

.grid-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    /* Tự động chia cột */
    gap: 24px;
}

/* --- CARDS --- */
.card {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 32px;
    transition: all 0.3s ease;
    position: relative;
    cursor: default;
}

.card:hover {
    transform: translateY(-5px);
    /* Nổi lên khi hover */
    box-shadow: 0 12px 24px rgba(0, 0, 0, 0.05);
    border-color: #d1d5db;
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
}

.tag {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    text-transform: uppercase;
    color: var(--text-secondary);
    letter-spacing: 0.05em;
}

.status-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    display: block;
}

.status-dot.green {
    background-color: #10B981;
    box-shadow: 0 0 8px #10B981;
}

.status-dot.yellow {
    background-color: #F59E0B;
}

.status-dot.blue {
    background-color: #3B82F6;
}

.status-dot.purple {
    background-color: #8B5CF6;
}

.card h3 {
    font-size: 1.5rem;
    margin-bottom: 12px;
    font-weight: 600;
}

.card p {
    color: var(--text-secondary);
    margin-bottom: 24px;
    font-size: 0.95rem;
}

.tech-stack {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
}

.tech-stack span {
    background: #F3F4F6;
    color: #374151;
    padding: 4px 10px;
    border-radius: 4px;
    font-size: 0.8rem;
    font-weight: 500;
    font-family: var(--font-mono);
}

/* --- FOOTER --- */
.site-footer {
    border-top: 1px solid var(--border-color);
    padding: 40px 0;
    margin-top: 80px;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.social-links a {
    color: var(--text-secondary);
    margin-left: 20px;
    text-decoration: none;
    transition: color 0.2s;
}

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

/* --- RESPONSIVE --- */
@media (max-width: 768px) {
    .hero-title {
        font-size: 2.5rem;
    }

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

    .footer-content {
        flex-direction: column;
        gap: 20px;
        text-align: center;
    }

    .social-links a {
        margin: 0 10px;
    }
}

/* Thêm vào cuối file style.css gốc */

.card-link {
    text-decoration: none;
    /* Bỏ gạch chân link */
    color: inherit;
    /* Giữ màu chữ gốc */
    display: block;
    /* Để thẻ a bao trùm toàn bộ card */
    height: 100%;
}

.card-link .card {
    height: 100%;
    /* Đảm bảo card cao đều nhau */
    transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
}

/* Hiệu ứng khi hover vào thẻ a thì card sẽ nổi lên */
.card-link:hover .card {
    transform: translateY(-5px);
    box-shadow: 0 12px 24px rgba(0, 0, 0, 0.08);
    border-color: var(--accent-color);
    /* Viền đổi màu xanh/tím */
}