/* Reset & Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #00d4ff;
    --secondary-color: #0099cc;
    --dark-bg: #0f1419;
    --light-text: #ffffff;
    --card-bg: #1a1f2e;
    --border-color: #2d3748;
    --accent-color: #ff6b9d;
    --success-color: #52c41a;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--dark-bg);
    color: var(--light-text);
    line-height: 1.6;
}

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

/* Header & Navigation */
.header {
    background: linear-gradient(135deg, #0f1419 0%, #1a1f2e 100%);
    border-bottom: 2px solid var(--primary-color);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 4px 12px rgba(0, 212, 255, 0.1);
}

.navbar {
    padding: 1rem 0;
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo h1 {
    font-size: 1.8rem;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-weight: 700;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-links a {
    color: var(--light-text);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid transparent;
}

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

/* Hero Section */
.hero {
    background: linear-gradient(135deg, #0f1419 0%, #1a2a3a 50%, #0f1419 100%);
    padding: 6rem 0;
    text-align: center;
    border-bottom: 1px solid var(--border-color);
}

.hero h2 {
    font-size: 3.5rem;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, var(--primary-color), var(--light-text));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-weight: 700;
}

.hero p {
    font-size: 1.3rem;
    color: #a0aec0;
    margin-bottom: 2rem;
}

.cta-btn {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: var(--dark-bg);
    padding: 1rem 2.5rem;
    font-size: 1.1rem;
    border: none;
    border-radius: 50px;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(0, 212, 255, 0.3);
}

.cta-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 212, 255, 0.5);
}

/* Calculator Categories */
.calculators-section {
    padding: 4rem 0;
    border-bottom: 1px solid var(--border-color);
}

.calculators-section h3,
.popular-section h3,
.about-section h3 {
    font-size: 2.5rem;
    margin-bottom: 3rem;
    text-align: center;
    color: var(--primary-color);
}

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

.category-card {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
    text-align: center;
    cursor: pointer;
}

.category-card:hover {
    border-color: var(--primary-color);
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0, 212, 255, 0.2);
    background: linear-gradient(135deg, var(--card-bg) 0%, #242b3a 100%);
}

.category-card .icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.category-card h4 {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
    color: var(--primary-color);
}

.category-card p {
    color: #a0aec0;
    font-size: 0.95rem;
}

/* Popular Calculators */
.popular-section {
    padding: 4rem 0;
    border-bottom: 1px solid var(--border-color);
}

.calculators-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
}

.calc-item {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 8px;
    border-left: 4px solid var(--primary-color);
    display: flex;
    gap: 1.5rem;
    transition: all 0.3s ease;
    cursor: pointer;
}

.calc-item:hover {
    transform: translateX(10px);
    box-shadow: 0 4px 15px rgba(0, 212, 255, 0.15);
    background: linear-gradient(135deg, var(--card-bg) 0%, #242b3a 100%);
}

.calc-item span {
    font-size: 2rem;
    min-width: 60px;
    display: flex;
    align-items: center;
}

.calc-item h5 {
    font-size: 1.1rem;
    margin-bottom: 0.3rem;
    color: var(--primary-color);
}

.calc-item p {
    color: #a0aec0;
    font-size: 0.9rem;
}

/* About Section */
.about-section {
    padding: 4rem 0;
    border-bottom: 1px solid var(--border-color);
}

.about-section p {
    font-size: 1.1rem;
    color: #a0aec0;
    margin-bottom: 2rem;
    line-height: 1.8;
}

.about-section ul {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    list-style: none;
    margin-top: 2rem;
}

.about-section li {
    padding: 1rem;
    background: var(--card-bg);
    border-radius: 8px;
    border-left: 4px solid var(--success-color);
    color: var(--light-text);
}

/* Footer */
.footer {
    background: #0a0d12;
    border-top: 1px solid var(--border-color);
    padding: 2rem 0;
    margin-top: 4rem;
}

.footer .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 2rem;
}

.footer p {
    color: #a0aec0;
}

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

.footer-links a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-links a:hover {
    color: var(--light-text);
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero h2 {
        font-size: 2rem;
    }

    .hero p {
        font-size: 1rem;
    }

    .nav-links {
        gap: 1rem;
    }

    .nav-links a {
        font-size: 0.9rem;
    }

    .calculators-section h3,
    .popular-section h3,
    .about-section h3 {
        font-size: 2rem;
    }

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

    .calculators-list {
        grid-template-columns: 1fr;
    }

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

    .footer-links {
        flex-direction: column;
        gap: 1rem;
    }
}

@media (max-width: 480px) {
    .logo h1 {
        font-size: 1.3rem;
    }

    .nav-links {
        gap: 0.5rem;
        font-size: 0.85rem;
    }

    .hero h2 {
        font-size: 1.5rem;
    }

    .cta-btn {
        padding: 0.8rem 1.5rem;
        font-size: 0.9rem;
    }
}