:root {
    --primary-color: #4361ee;
    --secondary-color: #3f37c9;
    --accent-color: #4895ef;
    --light-color: #f8f9fa;
    --dark-color: #212529;
    --success-color: #4cc9f0;
    --crypto-color: #9c27b0;
    --text-color: #4caf50;
    --image-color: #ff9800;
    --calc-color: #2196f3;
    --edu-color: #e91e63;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #f5f7fa 0%, #e4edf5 100%);
    color: #333;
    min-height: 100vh;
    /*padding-bottom: 60px;*/
}

.navbar {
    /*background: linear-gradient(to right, var(--primary-color), var(--secondary-color));*/
    /*box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);*/
}

.hero-section {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 80px 0 60px;
    margin-bottom: 40px;
    border-radius: 0 0 30px 30px;
    position: relative;
    overflow: hidden;
}

.hero-section::before {
    content: "";
    position: absolute;
    top: -80px;
    left: -50px;
    width: 250px;
    height: 250px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
}

.hero-section::after {
    content: "";
    position: absolute;
    bottom: -100px;
    right: -80px;
    width: 300px;
    height: 300px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
}

.section-title {
    position: relative;
    margin-bottom: 30px;
    padding-bottom: 15px;
    color: var(--secondary-color);
    font-weight: 700;
}

.section-title::after {
    content: "";
    position: absolute;
    left: 0;
    bottom: 0;
    width: 60px;
    height: 4px;
    background: var(--accent-color);
    border-radius: 2px;
}

.category-card {
    transition: all 0.3s ease;
    border: none;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 6px 15px rgba(0, 0, 0, 0.08);
    margin-bottom: 25px;
    height: 100%;
    background: white;
}

.category-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 12px 25px rgba(0, 0, 0, 0.15);
}

.category-header {
    background: linear-gradient(to right, var(--primary-color), var(--accent-color));
    color: white;
    padding: 20px;
    font-weight: 700;
    font-size: 1.2rem;
}

.tool-card {
    transition: all 0.3s ease;
    border: none;
    border-radius: 12px;
    overflow: hidden;
    background: white;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.05);
    margin-bottom: 15px;
    height: 100%;
    display: flex;
    flex-direction: column;
}

.tool-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.1);
}

.tool-card .card-body {
    padding: 20px;
    flex-grow: 1;
}

.tool-card .card-title {
    font-weight: 600;
    color: var(--dark-color);
    margin-bottom: 10px;
    font-size: 1.1rem;
}

.tool-card .card-text {
    color: #666;
    font-size: 0.9rem;
    flex-grow: 1;
}

.tool-icon {
    width: 50px;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 12px;
    margin-bottom: 15px;
    font-size: 1.5rem;
}

.date-icon {
    background: linear-gradient(135deg, #4cc9f0, #4895ef);
}

.conversion-icon {
    background: linear-gradient(135deg, #f72585, #b5179e);
}

.json-icon {
    background: linear-gradient(135deg, #7209b7, #560bad);
}

.crypto-icon {
    background: linear-gradient(135deg, #9c27b0, #7b1fa2);
}

.text-icon {
    background: linear-gradient(135deg, #4caf50, #2e7d32);
}

.image-icon {
    background: linear-gradient(135deg, #ff9800, #ef6c00);
}

.calc-icon {
    background: linear-gradient(135deg, #2196f3, #0d47a1);
}

.edu-icon {
    background: linear-gradient(135deg, #e91e63, #c2185b);
}

.btn-tool {
    background: linear-gradient(to right, var(--primary-color), var(--accent-color));
    border: none;
    border-radius: 8px;
    padding: 8px 20px;
    font-weight: 600;
    transition: all 0.3s ease;
    width: 100%;
    color: white;
    text-decoration: none;
    text-align: center;
    display: block;
}

.btn-tool:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 15px rgba(67, 97, 238, 0.4);
    color: white;
}

.feature-box {
    background: white;
    border-radius: 15px;
    padding: 25px;
    box-shadow: 0 6px 15px rgba(0, 0, 0, 0.05);
    text-align: center;
    margin-bottom: 30px;
    transition: all 0.3s ease;
}

.feature-box:hover {
    transform: translateY(-8px);
    box-shadow: 0 12px 25px rgba(0, 0, 0, 0.1);
}

.feature-icon {
    font-size: 2.5rem;
    margin-bottom: 20px;
    color: var(--primary-color);
}

.footer {
    background: linear-gradient(to right, var(--secondary-color), var(--primary-color));
    color: white;
    padding: 30px 0;
    margin-top: 50px;
}

.tool-category {
    margin-bottom: 50px;
}

.stats-badge {
    background: rgba(255, 255, 255, 0.2);
    border-radius: 20px;
    padding: 3px 12px;
    font-size: 0.8rem;
    font-weight: 600;
}

.category-nav {
    position: sticky;
    top: 0;
    background: white;
    border-radius: 15px;
    padding: 10px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.08);
    margin-bottom: 30px;
    z-index: 100;
}

.category-nav .nav-link {
    padding: 8px 15px;
    border-radius: 8px;
    font-weight: 600;
    color: #555;
    transition: all 0.3s;
}

.category-nav .nav-link:hover,
.category-nav .nav-link.active {
    background: linear-gradient(to right, var(--primary-color), var(--accent-color));
    color: white;
}

@media (max-width: 768px) {
    .hero-section {
        padding: 50px 0 40px;
    }

    .hero-section h1 {
        font-size: 1.8rem;
    }

    .section-title {
        font-size: 1.5rem;
    }

    .category-nav {
        position: static;
        margin-bottom: 20px;
    }
}