/* Global Styles */
:root {
    --primary-color: #4f46e5;
    --secondary-color: #6b7280;
    --background-color: #f3f4f6;
    --text-color: #1f2937;
    --border-color: #e5e7eb;
}

/* Dark Theme */
[data-theme="dark"] {
    --primary-color: #818cf8;
    --secondary-color: #9ca3af;
    --background-color: #1f2937;
    --text-color: #f9fafb;
    --border-color: #374151;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--background-color);
}

/* Header Styles */
.header {
    background-color: white;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-brand {
    font-size: 1.5rem;
    font-weight: bold;
}

.logo {
    color: var(--primary-color);
    text-decoration: none;
}

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

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

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

.nav-links a.active {
    color: var(--primary-color);
    font-weight: 600;
}

/* Theme Toggle */
.theme-toggle {
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
    color: var(--secondary-color);
}

.theme-toggle:hover {
    color: var(--primary-color);
}

/* Main Content */
.calculator-page {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

h1 {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-color);
    text-align: center;
    margin-bottom: 1rem;
}

h2 {
    font-size: 2rem;
    font-weight: 600;
    color: var(--text-color);
    margin-bottom: 1rem;
}

h3 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-color);
    margin-bottom: 1rem;
}

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

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    text-align: center;
    color: var(--secondary-color);
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }

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

    .calculator-page {
        padding: 1rem;
    }

    h1 {
        font-size: 2rem;
    }

    h2 {
        font-size: 1.75rem;
    }

    h3 {
        font-size: 1.25rem;
    }
}