:root {
    --primary-color: #6366f1; /* Indigo */
    --primary-hover: #4f46e5;
    --success-color: #16a34a;
    --success-hover: #218838;
    --secondary-color: #6c757d;
    --light-gray: #f8fafc;
    --border-color: #e2e8f0;
    --text-color: #1e293b;
    --text-muted: #6c757d;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.05), 0 10px 20px rgba(0, 0, 0, 0.07);
}

*, *::before, *::after {
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--light-gray);
    color: var(--text-color);
    margin: 0;
    line-height: 1.6;
}

.container { max-width: 1600px; margin: 0 auto; padding: 0 2rem; }

/* App Navbar */
.app-navbar { background: var(--white); border-bottom: 1px solid var(--border-color); padding: 0.75rem 0; }
.app-navbar .container { display: flex; justify-content: space-between; align-items: center; }
.logo { font-size: 1.25rem; font-weight: 700; text-decoration: none; color: var(--primary-color); }
.app-navbar nav { display: flex; align-items: center; gap: 1rem; }
.nav-link { text-decoration: none; color: var(--text-muted); font-weight: 500; transition: color 0.2s; }
.nav-link:hover { color: var(--primary-color); }
.button-secondary { background-color: var(--light-gray); border: 1px solid var(--border-color); color: var(--text-color); padding: 0.5rem 1rem; font-size: 0.9rem; border-radius: 0.5rem; cursor: pointer; font-weight: 600; transition: all 0.2s; }

.app-wrapper {
    background: white;
    padding: 2rem 2.5rem;
    border-radius: 16px;
    box-shadow: var(--shadow);
    width: 100%;
    max-width: 700px;
    margin: 2rem auto;
}
h1 {
    color: var(--primary-color);
    margin-bottom: 2rem;
    text-align: center;
    font-weight: 700;
    letter-spacing: -1px;
}
fieldset {
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
}
fieldset:disabled { opacity: 0.5; }
legend {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--primary-color);
    padding: 0 10px;
}
label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    font-size: 0.9rem;
}
input[type="text"], input[type="password"] {
    width: 100%;
    padding: 12px 15px;
    margin-bottom: 1rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-family: inherit;
    background-color: white;
    transition: border-color 0.2s, box-shadow 0.2s;
}
input[type="text"]:focus, input[type="password"]:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.25);
}
input[readonly] { background-color: #e9ecef; cursor: not-allowed; }
.drop-zone {
    border: 2px dashed var(--border-color);
    border-radius: 12px;
    padding: 2rem;
    text-align: center;
    cursor: pointer;
    transition: background-color 0.2s, border-color 0.2s;
    margin-bottom: 1rem;
    background-color: #fff;
}
.drop-zone p { margin: 0; font-weight: 600; font-size: 1rem; color: var(--text-color); }
.drop-zone span { font-size: 0.9em; color: var(--text-muted); }
.drop-zone.drag-over {
    background-color: rgba(99, 102, 241, 0.05);
    border-color: var(--primary-color);
}
.thumbnail-preview-container {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 1rem;
    padding: 10px;
    background-color: var(--light-gray);
    border-radius: 8px;
    min-height: 90px;
}
.thumbnail-item {
    position: relative;
    width: 70px;
    height: 70px;
    border-radius: 8px;
    overflow: hidden;
    background-color: var(--border-color);
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    cursor: grab;
    transition: transform 0.2s;
}
.thumbnail-item:hover {
    transform: scale(1.05);
    box-shadow: 0 4px 8px rgba(0,0,0,0.15);
}
.thumbnail-item img { width: 100%; height: 100%; object-fit: cover; }
.thumbnail-delete {
    position: absolute;
    top: -5px;
    right: -5px;
    width: 22px;
    height: 22px;
    background-color: rgba(0, 0, 0, 0.7);
    color: white;
    border: 2px solid white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 16px;
    font-weight: bold;
    cursor: pointer;
    line-height: 20px;
    padding: 0;
    opacity: 0;
    transform: scale(0.8);
    transition: opacity 0.2s, transform 0.2s;
}
.thumbnail-item:hover .thumbnail-delete { opacity: 1; transform: scale(1); }
.sortable-ghost { opacity: 0.4; background: #c8ebfb; }
button {
    width: 100%;
    background-color: var(--success-color);
    color: white;
    border: none;
    padding: 14px 20px;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 600;
    transition: background-color 0.2s, transform 0.1s;
}
button:hover { background-color: var(--success-hover); transform: translateY(-1px); }
button:disabled { background-color: #cccccc; cursor: not-allowed; transform: none; }
#step1Button { background-color: var(--primary-color); }
#step1Button:hover { background-color: var(--primary-hover); }
#progress-container { margin-top: 1.5rem; padding: 1rem; border: 1px solid var(--border-color); border-radius: 12px; background-color: var(--light-gray); }
#progress-text { margin: 0 0 10px 0; font-weight: 500; }
progress { width: 100%; height: 12px; border-radius: 6px; overflow: hidden; border: none; }
progress::-webkit-progress-bar { background-color: var(--border-color); }
progress::-webkit-progress-value { background-color: var(--primary-color); transition: width 0.3s ease; }
#progress-log { margin-top: 10px; font-size: 0.85em; max-height: 150px; overflow-y: auto; background: #fff; padding: 10px; border-radius: 8px; border: 1px solid var(--border-color); }

/* Responsive */
@media (max-width: 768px) {
    body { padding: 0; }
    .app-wrapper { padding: 1.5rem; margin: 0; border-radius: 0; box-shadow: none; }
    .app-navbar .container { padding: 0 1rem; }
    .app-navbar nav { display: none; }
}