/* Base styles */
:root {
    --primary-color: #1a202c;
    --secondary-color: #2d3748;
    --accent-color: #4a5568;
    --background-color: #ffffff;
    --error-color: #e53e3e;
    --success-color: #2f855a;
    --heading-color: #1a202c;  /* New: Heading color for light mode */
}

/* Typography */
body {
    font-family: 'Inter', sans-serif;
    line-height: 1.5;
    color: var(--primary-color);
    background-color: var(--background-color);
}

/* Layout */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

/* Header */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: var(--background-color);
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    z-index: 1000;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 4rem;
}

/* Navigation */
.nav-menu {
    display: flex;
    gap: 2rem;
}

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

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

/* Mobile Navigation */
.mobile-menu-button {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

/* Hero Section */
.hero {
    padding-top: 4rem;
    background-color: var(--primary-color);
    color: white;
    text-align: center;
    min-height: 60vh;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Calculator Cards */
.calculator-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    padding: 2rem 0;
}

.calculator-card {
    background: white;
    border-radius: 0.5rem;
    padding: 1.5rem;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    transition: transform 0.3s ease;
}

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

/* Forms */
.form-group {
    margin-bottom: 1rem;
}

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

.form-input {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid #e2e8f0;
    border-radius: 0.375rem;
    transition: border-color 0.3s ease;
}

.form-input:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(74,85,104,0.2);
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 0.375rem;
    font-weight: 500;
    text-align: center;
    transition: all 0.3s ease;
    cursor: pointer;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
}

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

/* Results Display */
.results {
    margin-top: 2rem;
    padding: 1.5rem;
    background-color: #f7fafc;
    border-radius: 0.5rem;
}

/* Error Messages */
.error {
    color: var(--error-color);
    font-size: 0.875rem;
    margin-top: 0.5rem;
}

/* Success Messages */
.success {
    color: var(--success-color);
    font-size: 0.875rem;
    margin-top: 0.5rem;
}

/* Footer */
.footer {
    background-color: var(--primary-color);
    color: white;
    padding: 3rem 0;
    margin-top: 4rem;
}

/* Utilities */
.text-center {
    text-align: center;
}

.mt-4 {
    margin-top: 1rem;
}

.mb-4 {
    margin-bottom: 1rem;
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    animation: fadeIn 0.3s ease-out;
}

/* Print Styles */
@media print {
    .header,
    .footer,
    .no-print {
        display: none;
    }
    
    .container {
        width: 100%;
        max-width: none;
        padding: 0;
    }
}