/* Reset and base styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: #1a1a1a;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 50%, #f093fb 100%);
    min-height: 100vh;
    overflow-x: hidden;
}

/* Navigation */
.navbar {
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.2);
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.12);
    transition: all 0.3s ease;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-brand {
    display: flex;
    align-items: center;
    font-size: 1.5rem;
    font-weight: 700;
    color: #4c51bf;
}

.nav-brand i {
    margin-right: 0.5rem;
    font-size: 1.8rem;
}

/* Buttons */
.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 8px;
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
}

.btn-primary {
    background: linear-gradient(135deg, #4c51bf, #667eea);
    color: white;
    box-shadow: 0 4px 15px rgba(76, 81, 191, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(76, 81, 191, 0.4);
}

.btn-secondary {
    background: #f7fafc;
    color: #4a5568;
    border: 1px solid #e2e8f0;
}

.btn-secondary:hover {
    background: #edf2f7;
}

/* Main content */
.main-content {
    min-height: calc(100vh - 80px);
}

/* Hero section */
.hero {
    padding: 6rem 2rem 5rem;
    text-align: center;
    color: white;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 30% 20%, rgba(255, 255, 255, 0.1) 0%, transparent 50%),
                radial-gradient(circle at 70% 80%, rgba(255, 255, 255, 0.08) 0%, transparent 50%);
    pointer-events: none;
}

.hero-content {
    position: relative;
    z-index: 1;
    animation: fadeInUp 1s ease-out;
}

.hero-content h1 {
    font-size: 4rem;
    font-weight: 800;
    margin-bottom: 1.5rem;
    text-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
    background: linear-gradient(135deg, #ffffff 0%, #f0f8ff 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1.1;
}

.hero-content p {
    font-size: 1.4rem;
    opacity: 0.95;
    max-width: 700px;
    margin: 0 auto;
    text-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
    font-weight: 400;
    line-height: 1.6;
}

/* Kits section */
.kits-section {
    background: linear-gradient(180deg, #ffffff 0%, #fafbff 100%);
    padding: 5rem 2rem 6rem;
    margin-top: -3rem;
    border-radius: 3rem 3rem 0 0;
    box-shadow: 0 -8px 40px rgba(0, 0, 0, 0.15);
    position: relative;
}

.kits-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent 0%, rgba(102, 126, 234, 0.3) 50%, transparent 100%);
}

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

.kits-section h2 {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 600;
    margin-bottom: 3rem;
    color: #2d3748;
}

/* Filters Bar */
.filters-bar {
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    border-radius: 16px;
    padding: 1.5rem;
    margin-bottom: 2rem;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.search-box {
    position: relative;
    margin-bottom: 1rem;
}

.search-box i {
    position: absolute;
    left: 1rem;
    top: 50%;
    transform: translateY(-50%);
    color: #a0aec0;
    font-size: 1rem;
}

.search-box input {
    width: 100%;
    padding: 1rem 1rem 1rem 2.5rem;
    border: 1px solid #e2e8f0;
    border-radius: 12px;
    font-size: 1rem;
    transition: all 0.2s ease;
    background: white;
}

.search-box input:focus {
    outline: none;
    border-color: #4c51bf;
    box-shadow: 0 0 0 3px rgba(76, 81, 191, 0.1);
}

.filter-buttons {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.filter-buttons select {
    padding: 0.75rem 1rem;
    border: 1px solid #e2e8f0;
    border-radius: 8px;
    font-size: 0.9rem;
    background: white;
    color: #4a5568;
    min-width: 140px;
    transition: all 0.2s ease;
}

.filter-buttons select:focus {
    outline: none;
    border-color: #4c51bf;
    box-shadow: 0 0 0 3px rgba(76, 81, 191, 0.1);
}

/* Kits grid */
.kits-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 2rem;
}

.kit-card {
    background: white;
    border-radius: 16px;
    padding: 2rem;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    border: 1px solid rgba(0, 0, 0, 0.05);
    transition: all 0.3s ease;
    position: relative;
}

.kit-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.12);
}

.kit-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 1rem;
}

.kit-type {
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.kit-type.quizlet {
    background: #e3f2fd;
    color: #1976d2;
}

.kit-type.blooket {
    background: #f3e5f5;
    color: #7b1fa2;
}

.kit-protected {
    color: #f59e0b;
    font-size: 1.2rem;
}

.kit-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: #2d3748;
}

.kit-description {
    color: #718096;
    margin-bottom: 1rem;
    line-height: 1.5;
}

.kit-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.25rem;
    margin-bottom: 1rem;
}

.kit-tag {
    background: #edf2f7;
    color: #4a5568;
    padding: 0.25rem 0.5rem;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 500;
}

.kit-tag.subject-math { background: #fef5e7; color: #d69e2e; }
.kit-tag.subject-english { background: #e6fffa; color: #319795; }
.kit-tag.subject-science { background: #e3f2fd; color: #1976d2; }
.kit-tag.subject-social { background: #f3e5f5; color: #7b1fa2; }
.kit-tag.subject-social-studies { background: #f3e5f5; color: #7b1fa2; }
.kit-tag.subject-history { background: #fff5f5; color: #e53e3e; }
.kit-tag.subject-biology { background: #f0fff4; color: #38a169; }
.kit-tag.subject-chemistry { background: #fef5e7; color: #d69e2e; }
.kit-tag.subject-physics { background: #e3f2fd; color: #1976d2; }

.kit-date {
    font-size: 0.85rem;
    color: #a0aec0;
    margin-bottom: 1.5rem;
}

.kit-actions {
    display: flex;
    gap: 1rem;
}

.btn-kit {
    flex: 1;
    justify-content: center;
    font-size: 0.9rem;
}

/* Loading state */
.loading {
    grid-column: 1 / -1;
    text-align: center;
    padding: 4rem;
    color: #718096;
}

.loading i {
    font-size: 2rem;
    margin-bottom: 1rem;
    display: block;
}

/* Modals */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
    z-index: 2000;
    animation: fadeIn 0.3s ease;
}

.modal.active {
    display: flex;
    align-items: center;
    justify-content: center;
}

.modal-content {
    background: white;
    border-radius: 16px;
    width: 90%;
    max-width: 500px;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    animation: slideUp 0.3s ease;
}

.modal-header {
    padding: 2rem 2rem 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid #e2e8f0;
}

.modal-header h3 {
    font-size: 1.5rem;
    font-weight: 600;
    color: #2d3748;
}

.close-btn {
    background: none;
    border: none;
    font-size: 1.5rem;
    color: #718096;
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 8px;
    transition: all 0.2s ease;
}

.close-btn:hover {
    background: #f7fafc;
    color: #4a5568;
}

.modal-body {
    padding: 2rem;
}

/* Form styles */
.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: #4a5568;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid #e2e8f0;
    border-radius: 8px;
    font-size: 1rem;
    transition: all 0.2s ease;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: #4c51bf;
    box-shadow: 0 0 0 3px rgba(76, 81, 191, 0.1);
}

.checkbox-group {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.checkbox-group input[type="checkbox"] {
    width: auto;
    margin: 0;
}

.form-actions {
    display: flex;
    gap: 1rem;
    justify-content: flex-end;
    margin-top: 2rem;
}

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Responsive design */
@media (max-width: 768px) {
    .nav-container {
        padding: 1rem;
    }
    
    .hero-content h1 {
        font-size: 2.5rem;
    }
    
    .hero-content p {
        font-size: 1.1rem;
    }
    
    .kits-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .kit-card {
        padding: 1.5rem;
    }
    
    .modal-content {
        margin: 1rem;
        width: calc(100% - 2rem);
    }
    
    .modal-header,
    .modal-body {
        padding: 1.5rem;
    }
    
    .form-actions {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
        justify-content: center;
    }
    
    .filter-buttons {
        flex-direction: column;
    }
    
    .filter-buttons select {
        width: 100%;
        min-width: auto;
    }
}

/* Error and success states */
.error {
    color: #e53e3e;
    font-size: 0.875rem;
    margin-top: 0.5rem;
}

.success {
    color: #38a169;
    font-size: 0.875rem;
    margin-top: 0.5rem;
}

.form-group.error input,
.form-group.error select,
.form-group.error textarea {
    border-color: #e53e3e;
}

.form-group.error input:focus,
.form-group.error select:focus,
.form-group.error textarea:focus {
    box-shadow: 0 0 0 3px rgba(229, 62, 62, 0.1);
}