:root {
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --success-color: #10b981;
    --error-color: #ef4444;
    --warning-color: #f59e0b;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-300: #d1d5db;
    --gray-600: #4b5563;
    --gray-800: #1f2937;
    --gray-900: #111827;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
    color: var(--gray-900);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    background: white;
    border-radius: 16px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    padding: 40px;
}

header {
    text-align: center;
    margin-bottom: 40px;
    padding-bottom: 20px;
    border-bottom: 3px solid var(--primary-color);
}

.event-badge {
    display: inline-block;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 8px 20px;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 600;
    margin-bottom: 15px;
    letter-spacing: 0.5px;
}

h1 {
    font-size: 2.5rem;
    color: var(--gray-900);
    margin-bottom: 10px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.subtitle {
    font-size: 1.1rem;
    color: var(--gray-600);
    margin-bottom: 8px;
}

.selection-info {
    font-size: 1rem;
    color: var(--primary-color);
    font-weight: 600;
    margin-top: 10px;
}

.breadcrumb {
    margin-top: 15px;
    padding: 10px 15px;
    background: var(--gray-100);
    border-radius: 6px;
    font-size: 0.9rem;
    color: var(--gray-700);
}

.view {
    display: block;
}

.back-btn {
    margin-bottom: 20px;
}

.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
    margin: 20px 0;
}

.card {
    padding: 24px;
    background: white;
    border: 2px solid var(--gray-200);
    border-radius: 12px;
    transition: all 0.3s ease;
}

.card.clickable {
    cursor: pointer;
}

.card.clickable:hover {
    border-color: var(--primary-color);
    transform: translateY(-4px);
    box-shadow: 0 8px 16px rgba(37, 99, 235, 0.2);
}

.card h3 {
    font-size: 1.2rem;
    color: var(--gray-900);
    margin-bottom: 10px;
}

.card-description {
    color: var(--gray-600);
    line-height: 1.6;
    font-size: 0.95rem;
}

.use-case-card {
    position: relative;
}

.use-case-card.taken {
    background: var(--gray-100);
    border-color: var(--gray-300);
    opacity: 0.6;
    cursor: not-allowed;
}

.use-case-card.available {
    border-color: var(--success-color);
    background: #f0fdf4;
}

.badge {
    display: inline-block;
    font-size: 0.75rem;
    font-weight: 600;
    padding: 4px 10px;
    border-radius: 12px;
    margin-bottom: 10px;
}

.badge-available {
    background: #d1fae5;
    color: #065f46;
}

.badge-taken {
    background: var(--gray-200);
    color: var(--gray-600);
}

.case-study-header {
    background: var(--gray-100);
    padding: 20px;
    border-radius: 12px;
    margin-bottom: 20px;
}

.case-study-header h2 {
    color: var(--gray-900);
    margin-bottom: 10px;
}

.case-description {
    color: var(--gray-700);
    line-height: 1.6;
}

.info-box {
    background: var(--gray-100);
    padding: 20px;
    border-radius: 8px;
    margin-bottom: 30px;
    border-left: 4px solid var(--primary-color);
}

.info-box ul {
    margin-left: 20px;
    margin-top: 10px;
}

.info-box li {
    margin: 8px 0;
    color: var(--gray-700);
}

.selected-use-case {
    background: white;
    padding: 15px;
    border-radius: 8px;
    margin-bottom: 25px;
    border-left: 4px solid var(--primary-color);
    font-weight: 600;
}

.statements-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 15px;
    margin-bottom: 30px;
}

.statement-card {
    padding: 20px;
    border: 2px solid var(--gray-200);
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.3s ease;
    background: white;
    position: relative;
}

.statement-card:hover:not(.taken) {
    border-color: var(--primary-color);
    transform: translateY(-4px);
    box-shadow: 0 8px 16px rgba(37, 99, 235, 0.2);
}

.statement-card.selected {
    border-color: var(--primary-color);
    background: #eff6ff;
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.statement-card.taken {
    background: var(--gray-100);
    border-color: var(--gray-300);
    cursor: not-allowed;
    opacity: 0.6;
}

.statement-badge {
    display: inline-block;
    font-size: 0.75rem;
    font-weight: 600;
    padding: 4px 10px;
    border-radius: 12px;
    margin-bottom: 10px;
}

.badge-available {
    background: #d1fae5;
    color: #065f46;
}

.badge-taken {
    background: var(--gray-200);
    color: var(--gray-600);
}

.badge-selected {
    background: #dbeafe;
    color: #1e40af;
}

.statement-text {
    font-size: 1rem;
    color: var(--gray-800);
    line-height: 1.6;
}

.form-section {
    background: var(--gray-100);
    padding: 30px;
    border-radius: 12px;
    margin-top: 30px;
}

.form-section h2 {
    margin-bottom: 15px;
    color: var(--gray-900);
}

.selected-statement {
    background: white;
    padding: 15px;
    border-radius: 8px;
    margin-bottom: 25px;
    border-left: 4px solid var(--primary-color);
    font-style: italic;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--gray-700);
}

.form-group input {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--gray-300);
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.3s;
}

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

.form-group small {
    display: block;
    margin-top: 5px;
    color: var(--gray-600);
    font-size: 0.875rem;
}

.button-group {
    display: flex;
    gap: 15px;
    margin-top: 25px;
}

.btn {
    padding: 14px 28px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    flex: 1;
}

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

.btn-primary:hover:not(:disabled) {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3);
}

.btn-primary:disabled {
    background: var(--gray-300);
    cursor: not-allowed;
}

.btn-secondary {
    background: white;
    color: var(--gray-700);
    border: 2px solid var(--gray-300);
}

.btn-secondary:hover {
    background: var(--gray-100);
}

.success-box {
    background: linear-gradient(135deg, #d1fae5 0%, #a7f3d0 100%);
    padding: 40px;
    border-radius: 12px;
    text-align: center;
}

.success-box h2 {
    color: #065f46;
    margin-bottom: 20px;
}

.success-box p {
    margin: 10px 0;
    font-size: 1.1rem;
}

.success-note {
    margin-top: 20px;
    font-style: italic;
    color: var(--gray-700);
}

.loading {
    text-align: center;
    padding: 60px 20px;
    font-size: 1.2rem;
    color: var(--gray-600);
}

.error {
    background: #fee2e2;
    color: #991b1b;
    padding: 15px 20px;
    border-radius: 8px;
    margin-bottom: 20px;
    border-left: 4px solid var(--error-color);
}

.hidden {
    display: none !important;
}

.toast {
    position: fixed;
    bottom: 30px;
    right: 30px;
    padding: 16px 24px;
    border-radius: 8px;
    color: white;
    font-weight: 500;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
    z-index: 1000;
    animation: slideIn 0.3s ease;
}

@keyframes slideIn {
    from {
        transform: translateX(400px);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

.toast.success {
    background: var(--success-color);
}

.toast.error {
    background: var(--error-color);
}

footer {
    text-align: center;
    margin-top: 40px;
    padding-top: 20px;
    border-top: 1px solid var(--gray-200);
    color: var(--gray-600);
}

footer a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
}

footer a:hover {
    text-decoration: underline;
}

/* Responsive design */
@media (max-width: 768px) {
    .container {
        padding: 24px;
    }

    h1 {
        font-size: 1.8rem;
    }

    .statements-grid {
        grid-template-columns: 1fr;
    }

    .button-group {
        flex-direction: column;
    }

    .toast {
        right: 20px;
        left: 20px;
        bottom: 20px;
    }
}