:root {
    --primary-color: #0d6efd;
    --bg-color: #212529;
    --text-color: #f8f9fa;
    --card-bg: #343a40;
    --border-color: #495057;
    --input-bg: #2b3035;
    --input-text: #e9ecef;
    --card-header-bg: #2b3035;
    --card-header-text: #f8f9fa;
    --muted-text: #adb5bd;
}

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: background-color 0.3s ease, color 0.3s ease;
}

.card {
    background-color: var(--card-bg);
    border-color: var(--border-color);
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.card-header {
    background-color: var(--card-header-bg);
    color: var(--card-header-text);
    border-bottom-color: var(--border-color);
}

.card-title {
    color: var(--card-header-text);
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
}

.preview-item {
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 1.25rem;
    margin-bottom: 1rem;
    background-color: var(--card-bg);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.preview-item h6 {
    color: var(--text-color);
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
}

.preview-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.preview-item:last-child {
    margin-bottom: 0;
}

.preview-url {
    word-break: break-all;
    margin: 0.5rem 0;
}

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

.preview-url a:hover {
    text-decoration: underline;
}

.preview-meta {
    color: var(--muted-text);
    font-size: 0.875rem;
    margin-top: 0.5rem;
    line-height: 1.5;
}

.alert {
    margin-top: 1rem;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

.form-control {
    background-color: var(--input-bg);
    border-color: var(--border-color);
    color: var(--input-text);
    transition: border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
}

.form-control:focus {
    background-color: var(--input-bg);
    color: var(--input-text);
    border-color: var(--primary-color);
    box-shadow: 0 0 0 0.25rem rgba(13, 110, 253, 0.25);
}

.form-control::placeholder {
    color: var(--muted-text);
    opacity: 0.7;
}

.form-label {
    color: var(--text-color);
    font-weight: 500;
    margin-bottom: 0.5rem;
}

.btn {
    transition: all 0.2s ease;
    padding: 0.5rem 1rem;
}

.btn:active {
    transform: scale(0.98);
}

.btn-danger {
    background-color: #dc3545;
    border-color: #dc3545;
}

.btn-danger:hover {
    background-color: #bb2d3b;
    border-color: #b02a37;
}

.loading {
    opacity: 0.7;
    pointer-events: none;
}