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

:root {
    --primary: #3b82f6;
    --primary-dark: #2563eb;
    --secondary: #10b981;
    --dark: #1e293b;
    --light: #f8fafc;
    --gray: #64748b;
    --border: #e2e8f0;
    --shadow: 0 1px 3px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 25px -5px rgba(0,0,0,0.1);
}

[data-theme="dark"] {
    --dark: #f8fafc;
    --light: #0f172a;
    --border: #334155;
    --gray: #94a3b8;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--light);
    color: var(--dark);
    line-height: 1.6;
    transition: background 0.3s, color 0.3s;
}

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

/* Navigation */
.navbar {
    background: var(--dark);
    color: white;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: var(--shadow);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 20px;
}

.logo {
    color: white;
    font-size: 1.5rem;
    font-weight: bold;
    text-decoration: none;
}

.nav-menu {
    display: flex;
    gap: 2rem;
    align-items: center;
}

.nav-menu a {
    color: white;
    text-decoration: none;
    transition: opacity 0.3s;
}

.nav-menu a:hover { opacity: 0.8; }

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    color: white;
    font-size: 1.5rem;
    cursor: pointer;
}

.theme-btn {
    background: var(--primary);
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 2rem;
    cursor: pointer;
    color: white;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    padding: 4rem 0;
    text-align: center;
}

.hero h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.search-box {
    max-width: 500px;
    margin: 2rem auto 0;
}

.search-box input {
    width: 100%;
    padding: 1rem;
    border: none;
    border-radius: 2rem;
    font-size: 1rem;
}

/* Calculator Grid */
.calculator-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
}

.calculator-card {
    background: white;
    border-radius: 1rem;
    padding: 1.5rem;
    box-shadow: var(--shadow-lg);
    transition: transform 0.3s;
    text-align: center;
}

[data-theme="dark"] .calculator-card {
    background: #1e293b;
}

.calculator-card:hover {
    transform: translateY(-5px);
}

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

.calculator-card h3 {
    margin-bottom: 0.5rem;
}

.calculator-card p {
    color: var(--gray);
    margin-bottom: 1rem;
}

.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    background: var(--primary);
    color: white;
    text-decoration: none;
    border-radius: 2rem;
    border: none;
    cursor: pointer;
    transition: background 0.3s;
}

.btn:hover { background: var(--primary-dark); }

.btn-secondary {
    background: var(--gray);
}

/* Calculator Box */
.calculator-wrapper {
    display: grid;
    grid-template-columns: 1fr 300px;
    gap: 2rem;
    margin: 2rem 0;
}

.calculator-box {
    background: white;
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: var(--shadow-lg);
}

[data-theme="dark"] .calculator-box {
    background: #1e293b;
}

.input-group {
    margin-bottom: 1rem;
}

.input-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.input-group input, 
.input-group select {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border);
    border-radius: 0.5rem;
    background: var(--light);
    color: var(--dark);
}

.result-box {
    margin-top: 2rem;
    padding: 1rem;
    background: var(--light);
    border-radius: 0.5rem;
    text-align: center;
}

.result-value {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary);
    margin: 1rem 0;
}

/* Content Sections */
.content-section {
    margin: 3rem 0;
}

.content-section h2 {
    margin: 1.5rem 0 1rem;
}

.content-section pre {
    background: var(--dark);
    color: var(--light);
    padding: 1rem;
    border-radius: 0.5rem;
    overflow-x: auto;
}

/* Related Calculators */
.related-calculators {
    margin: 3rem 0;
    padding: 2rem;
    background: var(--light);
    border-radius: 1rem;
}

.related-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-top: 1rem;
}

.related-link {
    display: block;
    padding: 0.75rem;
    background: white;
    text-decoration: none;
    color: var(--primary);
    border-radius: 0.5rem;
    text-align: center;
    transition: all 0.3s;
}

.related-link:hover {
    background: var(--primary);
    color: white;
}

/* Ad Containers */
.ad-container {
    background: #f1f5f9;
    border: 2px dashed var(--border);
    text-align: center;
    padding: 1rem;
    margin: 1rem 0;
    border-radius: 0.5rem;
    color: var(--gray);
}

.sidebar-ad {
    height: 600px;
    position: sticky;
    top: 100px;
}

/* Footer */
footer {
    background: var(--dark);
    color: white;
    padding: 3rem 0 1rem;
    margin-top: 3rem;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section a {
    display: block;
    color: var(--gray);
    text-decoration: none;
    margin: 0.5rem 0;
    transition: color 0.3s;
}

.footer-section a:hover { color: white; }

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

/* Responsive */
@media (max-width: 768px) {
    .mobile-menu-btn { display: block; }
    .nav-menu {
        display: none;
        position: absolute;
        top: 60px;
        left: 0;
        right: 0;
        background: var(--dark);
        flex-direction: column;
        padding: 1rem;
    }
    .nav-menu.active { display: flex; }
    
    .calculator-wrapper {
        grid-template-columns: 1fr;
    }
    
    .hero h1 { font-size: 1.75rem; }
    
    .calculator-grid {
        grid-template-columns: 1fr;
    }
}

/* Utility Classes */
.text-center { text-align: center; }
.mt-2 { margin-top: 2rem; }
.mb-2 { margin-bottom: 2rem; }