:root {
    --primary-color: #2ecc71;
    --primary-dark: #27ae60;
    --bg-color: #f4f6f8;
    --card-bg: #ffffff;
    --text-color: #333333;
    --text-muted: #666666;
    --border-color: #e0e0e0;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --font-family: 'Inter', system-ui, -apple-system, sans-serif;
}

[data-theme="dark"] {
    --primary-color: #2ecc71;
    --primary-dark: #27ae60;
    --bg-color: #1a1a1a;
    --card-bg: #2d2d2d;
    --text-color: #e0e0e0;
    --text-muted: #aaaaaa;
    --border-color: #404040;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
}

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

body {
    font-family: var(--font-family);
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    transition: background-color 0.3s, color 0.3s;
}

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

/* Header */
header {
    background-color: var(--card-bg);
    box-shadow: var(--shadow);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-wrapper {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo i {
    font-size: 1.8rem;
}

.nav-links {
    display: flex;
    gap: 20px;
    align-items: center;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: color 0.2s;
}

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

.theme-toggle {
    background: none;
    border: none;
    color: var(--text-color);
    cursor: pointer;
    font-size: 1.2rem;
    padding: 5px;
    transition: color 0.2s;
}

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

/* Hero Section */
.hero {
    text-align: center;
    padding: 4rem 0;
}

.hero h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--primary-color);
}

.hero p {
    font-size: 1.1rem;
    color: var(--text-muted);
    max-width: 600px;
    margin: 0 auto;
}

/* Grid Layout */
.category-section {
    margin-bottom: 3rem;
}

.category-title {
    font-size: 1.5rem;
    color: var(--text-color);
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--primary-color);
    display: inline-block;
}

.calculator-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 20px;
}

.card {
    background-color: var(--card-bg);
    border-radius: 12px;
    padding: 20px;
    box-shadow: var(--shadow);
    transition: transform 0.2s, box-shadow 0.2s;
    text-decoration: none;
    color: var(--text-color);
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    border: 1px solid var(--border-color);
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 12px rgba(0, 0, 0, 0.15);
    border-color: var(--primary-color);
}

.card-icon {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 15px;
}

.card h3 {
    margin-bottom: 10px;
    font-size: 1.2rem;
}

.card p {
    font-size: 0.9rem;
    color: var(--text-muted);
}

/* Footer */
footer {
    background-color: var(--card-bg);
    padding: 2rem 0;
    margin-top: 4rem;
    border-top: 1px solid var(--border-color);
    text-align: center;
}

.footer-links {
    margin-bottom: 1rem;
}

.footer-links a {
    color: var(--text-muted);
    text-decoration: none;
    margin: 0 10px;
    font-size: 0.9rem;
}

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

.copyright {
    color: var(--text-muted);
    font-size: 0.85rem;
}

/* Calculator Page Specifics */
.calculator-container {
    background-color: var(--card-bg);
    border-radius: 12px;
    padding: 30px;
    box-shadow: var(--shadow);
    max-width: 800px;
    margin: 2rem auto;
}

.calc-header {
    margin-bottom: 2rem;
    text-align: center;
}

.calc-info {
    margin-top: 3rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
}

.calc-info h2 {
    margin-bottom: 1rem;
    color: var(--primary-color);
}

.form-group {
    margin-bottom: 1.5rem;
}

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

.form-control {
    width: 100%;
    padding: 10px 15px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background-color: var(--bg-color);
    color: var(--text-color);
    font-size: 1rem;
    transition: border-color 0.2s;
}

.form-control:focus {
    outline: none;
    border-color: var(--primary-color);
}

.btn {
    display: inline-block;
    padding: 12px 24px;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s;
    width: 100%;
}

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

.result-box {
    margin-top: 2rem;
    padding: 20px;
    background-color: var(--bg-color);
    border-radius: 8px;
    text-align: center;
    display: none;
    /* Hidden by default */
}

.result-box.show {
    display: block;
    animation: fadeIn 0.5s;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Layout for Calculator Pages with Sidebar */
.calc-page-layout {
    display: grid;
    grid-template-columns: 1fr 300px;
    gap: 30px;
    align-items: start;
}

.related-tools {
    background-color: var(--card-bg);
    padding: 20px;
    border-radius: 12px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    position: sticky;
    top: 100px;
    /* Sticky sidebar */
}

.related-tools h3 {
    font-size: 1.2rem;
    margin-bottom: 15px;
    color: var(--primary-color);
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 10px;
}

.related-list {
    list-style: none;
}

.related-list li {
    margin-bottom: 12px;
}

.related-list a {
    text-decoration: none;
    color: var(--text-color);
    display: flex;
    align-items: center;
    gap: 10px;
    transition: color 0.2s;
    font-size: 0.95rem;
}

.related-list a:hover {
    color: var(--primary-color);
}

.related-list i {
    width: 20px;
    text-align: center;
    color: var(--text-muted);
}

/* Responsive Design */
@media (max-width: 900px) {
    .calc-page-layout {
        grid-template-columns: 1fr;
    }

    .related-tools {
        position: static;
        margin-top: 30px;
    }
}