:root {
    --primary: #2563eb;
    --primary-hover: #1d4ed8;
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --text-main: #0f172a;
    --text-muted: #64748b;
    --border: #e2e8f0;
    --danger: #ef4444;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.5;
}

.hidden {
    display: none !important;
}

/* Modals */
.modal {
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(0,0,0,0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
}

.modal-content {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 8px;
    width: 90%;
    max-width: 400px;
    box-shadow: 0 4px 6px -1px rgba(0,0,0,0.1);
}

.modal h2 { margin-bottom: 1.5rem; text-align: center; }

input[type="password"], input[type="text"] {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border);
    border-radius: 4px;
    margin-bottom: 1rem;
    font-size: 1rem;
}

.btn {
    background: var(--primary);
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 4px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 500;
    display: inline-block;
    text-align: center;
    text-decoration: none;
}
.btn:hover { background: var(--primary-hover); }
.btn-secondary { background: var(--text-muted); }
.btn-secondary:hover { background: #475569; }
.btn-danger { background: var(--danger); padding: 0.25rem 0.5rem; font-size: 0.8rem;}

.error { color: var(--danger); margin-top: 0.5rem; font-size: 0.9rem; text-align: center; }

/* Layout */
header {
    background: var(--card-bg);
    padding: 1rem 2rem;
    border-bottom: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

main {
    padding: 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.breadcrumb {
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
    color: var(--text-muted);
}
.breadcrumb a {
    color: var(--primary);
    text-decoration: none;
    cursor: pointer;
}
.breadcrumb a:hover { text-decoration: underline; }

/* File Grid */
.file-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 1.5rem;
}

.file-item {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 1rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    cursor: pointer;
    transition: transform 0.1s, box-shadow 0.1s;
    position: relative;
}

.file-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 6px -1px rgba(0,0,0,0.1);
}

.file-icon {
    font-size: 3rem;
    margin-bottom: 0.5rem;
}

.file-name {
    font-size: 0.9rem;
    text-align: center;
    word-break: break-word;
    margin-bottom: 0.5rem;
    width: 100%;
}

.file-meta {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.delete-btn {
    position: absolute;
    top: 5px;
    right: 5px;
    display: none;
}
.file-item:hover .delete-btn {
    display: block;
}

/* Upload Progress */
#upload-progress {
    background: var(--card-bg);
    padding: 1rem;
    border-radius: 8px;
    border: 1px solid var(--border);
    margin-bottom: 1.5rem;
}
.progress-bar {
    width: 100%;
    height: 8px;
    background: var(--border);
    border-radius: 4px;
    margin-top: 0.5rem;
    overflow: hidden;
}
#progress-fill {
    height: 100%;
    background: var(--primary);
    width: 0%;
    transition: width 0.2s;
}

/* Preview Modal */
.preview-content {
    max-width: 800px;
    width: 95%;
    max-height: 90vh;
    display: flex;
    flex-direction: column;
}
.close-btn {
    position: absolute;
    top: 10px;
    right: 15px;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-muted);
}
#preview-container {
    flex-grow: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    margin: 1rem 0;
    background: #f1f5f9;
    border-radius: 4px;
    min-height: 200px;
}
#preview-container img, #preview-container video {
    max-width: 100%;
    max-height: 60vh;
    object-fit: contain;
}
#preview-container iframe {
    width: 100%;
    height: 60vh;
    border: none;
}
.preview-actions {
    display: flex;
    justify-content: center;
}