:root {
    --primary: #4361ee;
    --secondary: #3f37c9;
    --accent: #f72585;
    --light: #f8f9fa;
    --dark: #212529;
    --gray: #6c757d;
    --shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: #f5f7ff;
    color: var(--dark);
    line-height: 1.6;
}

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

/* Breadcrumb */
.breadcrumb {
    padding: 15px 0;
    font-size: 14px;
    color: var(--gray);
}

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

.breadcrumb a:hover {
    text-decoration: underline;
}

/* Calculator Categories */
.categories-section {
    margin: 40px 0;
}

.categories-section h2 {
    color: var(--primary);
    margin-bottom: 30px;
    font-size: 1.8rem;
    text-align: center;
}

.category-tabs {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 15px;
    margin-bottom: 30px;
}

.category-tab {
    padding: 10px 20px;
    background: white;
    border-radius: 30px;
    cursor: pointer;
    font-weight: 600;
    box-shadow: var(--shadow);
    transition: all 0.3s;
}

.category-tab.active {
    background: var(--primary);
    color: white;
}

.category-tab:hover:not(.active) {
    background: rgba(67, 97, 238, 0.1);
}

/* Calculators Grid */
.calculators-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 25px;
    margin-top: 30px;
}

.calculator-card {
    background: white;
    border-radius: 10px;
    padding: 25px;
    box-shadow: var(--shadow);
    transition: transform 0.3s;
    border-top: 4px solid var(--primary);
}

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

.calculator-icon {
    width: 60px;
    height: 60px;
    background: rgba(67, 97, 238, 0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
    color: var(--primary);
    font-size: 24px;
}

.calculator-card h3 {
    color: var(--primary);
    margin-bottom: 15px;
    font-size: 1.3rem;
}

.calculator-card p {
    color: var(--gray);
    margin-bottom: 20px;
}

.calculator-card a {
    display: inline-flex;
    align-items: center;
    color: var(--primary);
    font-weight: 500;
    text-decoration: none;
    transition: color 0.3s;
}

.calculator-card a:hover {
    color: var(--secondary);
}

.calculator-card a i {
    margin-left: 8px;
    transition: transform 0.3s;
}

.calculator-card a:hover i {
    transform: translateX(5px);
}

/* Popular Calculators */
.popular-section {
    margin: 60px 0 40px;
}

.popular-section h2 {
    color: var(--primary);
    margin-bottom: 30px;
    font-size: 1.8rem;
    text-align: center;
}

/* Responsive */
@media (max-width: 768px) {
    .nav-links {
        display: none;
    }

    .mobile-menu-btn {
        display: block;
    }

    .page-header h1 {
        font-size: 2rem;
    }

    .category-tabs {
        justify-content: flex-start;
    }
}

/* Hidden class for filtering */
.hidden {
    display: none !important;
    opacity: 0;
    height: 0;
    overflow: hidden;
}