/* Theme Xanh Tím Sang Trọng */
:root {
    --primary-color: #1e1b4b;
    /* Deep Indigo/Purple */
    --secondary-color: #2e1065;
    /* Deep Purple */
    --accent-color: #fbbf24;
    /* Vàng Gold làm điểm nhấn sang trọng */
    --accent-hover: #f59e0b;
    /* Vàng sáng hơn khi hover */
    --text-light: #f8fafc;
    /* Trắng sáng */
    --text-dark: #0f172a;
    /* Xanh Navy cực đậm để đọc trên nền trắng */
    --bg-light: #f1f5f9;
    /* Nền xám nhạt */
    --border-color: rgba(99, 102, 241, 0.3);
    /* Viền màu xanh nhạt mờ */
    --nav-height: 80px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', 'Roboto', sans-serif;
}

body {
    background-color: var(--primary-color);
    color: var(--text-light);
    line-height: 1.6;
}

a {
    text-decoration: none;
    color: inherit;
    transition: color 0.3s ease;
}

/* Typography */
h1,
h2,
h3,
h4,
h5,
h6 {
    color: var(--accent-color);
    font-weight: 600;
}

/* Header & Nav */
header {
    background-color: rgba(13, 27, 42, 0.95);
    backdrop-filter: blur(10px);
    position: sticky;
    top: 0;
    z-index: 1000;
    border-bottom: 1px solid var(--border-color);
    height: var(--nav-height);
    display: flex;
    align-items: center;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 20px;
}

.logo img {
    height: 50px;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 30px;
}

.nav-links a {
    font-size: 15px;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 1px;
}

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

.search-bar form {
    display: flex;
    border: 1px solid var(--accent-color);
    border-radius: 20px;
    overflow: hidden;
    background-color: transparent;
}

.search-bar input {
    background: transparent;
    border: none;
    padding: 8px 15px;
    color: var(--text-light);
    outline: none;
    width: 200px;
}

.search-bar input::placeholder {
    color: rgba(224, 225, 221, 0.5);
}

.search-bar button {
    background-color: transparent;
    border: none;
    color: var(--accent-color);
    padding: 8px 15px;
    cursor: pointer;
    transition: background-color 0.3s;
}

.search-bar button:hover {
    background-color: rgba(224, 169, 109, 0.1);
}

/* Hero Section */
.hero {
    padding: 60px 20px;
    text-align: center;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    position: relative;
    border-bottom: 1px solid var(--border-color);
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 20px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
}

.main-search-form {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    background: white;
    padding: 5px;
    border-radius: 30px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
}

.main-search-form input {
    flex-grow: 1;
    border: none;
    padding: 15px 25px;
    font-size: 1.1rem;
    border-radius: 25px 0 0 25px;
    outline: none;
    color: var(--text-dark);
}

.main-search-form button {
    background: var(--accent-color);
    color: var(--primary-color);
    border: none;
    padding: 15px 40px;
    font-size: 1.1rem;
    font-weight: bold;
    border-radius: 25px;
    cursor: pointer;
    transition: transform 0.2s, background 0.3s;
}

.main-search-form button:hover {
    background: var(--accent-hover);
    transform: scale(1.05);
}

/* Categories (Networks, Prices, Types) */
.section-title {
    text-align: center;
    font-size: 2rem;
    margin: 50px 0 30px;
    color: var(--accent-color);
}

.grid-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: grid;
    gap: 15px;
}

.grid-networks {
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
}

.grid-prices {
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
}

.grid-types {
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
}

.cat-box {
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 15px;
    text-align: center;
    background: rgba(27, 38, 59, 0.4);
    transition: all 0.3s ease;
    cursor: pointer;
}

.cat-box:hover {
    border-color: var(--accent-color);
    box-shadow: 0 0 15px rgba(224, 169, 109, 0.3);
    transform: translateY(-3px);
}

/* Footer */
footer {
    background-color: #0a111a;
    padding: 50px 20px 20px;
    margin-top: 60px;
    border-top: 1px solid var(--border-color);
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
}

.footer-col h4 {
    margin-bottom: 20px;
    font-size: 1.2rem;
}

.footer-col ul {
    list-style: none;
}

.footer-col ul li {
    margin-bottom: 10px;
    color: rgba(224, 225, 221, 0.7);
}

.footer-col ul li a:hover {
    color: var(--accent-color);
}

.footer-bottom {
    text-align: center;
    padding-top: 30px;
    margin-top: 30px;
    border-top: 1px solid rgba(224, 169, 109, 0.1);
    color: rgba(224, 225, 221, 0.5);
    font-size: 0.9rem;
}