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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
    position: relative;
    overflow-x: hidden;
}

.catalog-background {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: 
        radial-gradient(circle at 20% 50%, rgba(120, 119, 198, 0.3) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(255, 119, 198, 0.3) 0%, transparent 50%),
        radial-gradient(circle at 40% 20%, rgba(120, 219, 255, 0.2) 0%, transparent 50%);
    z-index: 0;
    animation: backgroundShift 20s ease-in-out infinite;
}

@keyframes backgroundShift {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.8;
    }
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
}

.catalog-header {
    text-align: center;
    margin-bottom: 40px;
    padding: 20px;
    animation: fadeInDown 0.6s ease-out;
}

.main-title {
    font-size: 2.5rem;
    font-weight: 700;
    color: #ffffff;
    margin-bottom: 10px;
    text-shadow: 2px 2px 8px rgba(0, 0, 0, 0.3);
}

.subtitle {
    font-size: 1.1rem;
    color: rgba(255, 255, 255, 0.9);
    font-weight: 300;
}

.tests-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 25px;
    padding: 20px 0;
}

.test-card {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 20px;
    padding: 30px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
    transition: all 0.3s ease;
    cursor: pointer;
    position: relative;
    overflow: hidden;
    animation: fadeInUp 0.6s ease-out;
    animation-fill-mode: both;
}

.test-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 5px;
    background: linear-gradient(90deg, #667eea, #764ba2, #f093fb);
    transform: scaleX(0);
    transform-origin: left;
    transition: transform 0.3s ease;
}

.test-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.3);
}

.test-card:hover::before {
    transform: scaleX(1);
}

.test-card:nth-child(1) {
    animation-delay: 0.1s;
}

.test-card:nth-child(2) {
    animation-delay: 0.2s;
}

.test-card:nth-child(3) {
    animation-delay: 0.3s;
}

.test-card:nth-child(4) {
    animation-delay: 0.4s;
}

.test-card:nth-child(5) {
    animation-delay: 0.5s;
}

.test-card:nth-child(6) {
    animation-delay: 0.6s;
}

.test-card:nth-child(7) {
    animation-delay: 0.7s;
}

.test-card:nth-child(8) {
    animation-delay: 0.8s;
}

.test-card:nth-child(9) {
    animation-delay: 0.9s;
}

.test-card:nth-child(10) {
    animation-delay: 1.0s;
}

.test-card:nth-child(11) {
    animation-delay: 1.1s;
}

.test-card:nth-child(12) {
    animation-delay: 1.2s;
}

.test-card:nth-child(13) {
    animation-delay: 1.3s;
}

.test-card:nth-child(14) {
    animation-delay: 1.4s;
}

.test-card:nth-child(15) {
    animation-delay: 1.5s;
}

.test-card:nth-child(16) {
    animation-delay: 1.6s;
}

.test-card:nth-child(17) {
    animation-delay: 1.7s;
}

@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.test-icon {
    font-size: 4rem;
    text-align: center;
    margin-bottom: 20px;
    animation: iconFloat 3s ease-in-out infinite;
}

.test-card:nth-child(1) .test-icon {
    animation-delay: 0s;
}

.test-card:nth-child(2) .test-icon {
    animation-delay: 0.5s;
}

.test-card:nth-child(3) .test-icon {
    animation-delay: 1s;
}

.test-card:nth-child(4) .test-icon {
    animation-delay: 1.5s;
}

.test-card:nth-child(5) .test-icon {
    animation-delay: 2s;
}

.test-card:nth-child(6) .test-icon {
    animation-delay: 2.5s;
}

.test-card:nth-child(7) .test-icon {
    animation-delay: 3s;
}

.test-card:nth-child(8) .test-icon {
    animation-delay: 3.5s;
}

.test-card:nth-child(9) .test-icon {
    animation-delay: 4s;
}

.test-card:nth-child(10) .test-icon {
    animation-delay: 4.5s;
}

.test-card:nth-child(11) .test-icon {
    animation-delay: 5s;
}

.test-card:nth-child(12) .test-icon {
    animation-delay: 5.5s;
}

.test-card:nth-child(13) .test-icon {
    animation-delay: 6s;
}

.test-card:nth-child(14) .test-icon {
    animation-delay: 6.5s;
}

.test-card:nth-child(15) .test-icon {
    animation-delay: 7s;
}

.test-card:nth-child(16) .test-icon {
    animation-delay: 7.5s;
}

.test-card:nth-child(17) .test-icon {
    animation-delay: 8s;
}

@keyframes iconFloat {
    0%, 100% {
        transform: translateY(0);
    }
    50% {
        transform: translateY(-10px);
    }
}

.test-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: #2d3748;
    margin-bottom: 15px;
    text-align: center;
}

.test-description {
    font-size: 1rem;
    color: #4a5568;
    line-height: 1.6;
    margin-bottom: 20px;
    text-align: center;
}

.test-link {
    display: block;
    width: 100%;
    padding: 15px 30px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    text-align: center;
    text-decoration: none;
    border-radius: 12px;
    font-weight: 600;
    font-size: 1rem;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.test-link::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.3);
    transform: translate(-50%, -50%);
    transition: width 0.6s, height 0.6s;
}

.test-link:hover::before {
    width: 300px;
    height: 300px;
}

.test-link:hover {
    transform: scale(1.05);
    box-shadow: 0 5px 20px rgba(102, 126, 234, 0.4);
}

.test-link:active {
    transform: scale(0.98);
}

.test-link-text {
    position: relative;
    z-index: 1;
}

@media (max-width: 768px) {
    .main-title {
        font-size: 2rem;
    }
    
    .subtitle {
        font-size: 1rem;
    }
    
    .tests-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    
    .test-card {
        padding: 25px;
    }
    
    .test-icon {
        font-size: 3rem;
    }
    
    .test-title {
        font-size: 1.3rem;
    }
}

@media (max-width: 480px) {
    body {
        padding: 10px;
    }
    
    .catalog-header {
        margin-bottom: 30px;
        padding: 15px;
    }
    
    .main-title {
        font-size: 1.8rem;
    }
    
    .test-card {
        padding: 20px;
    }
}