:root {
    --primary-gradient: linear-gradient(135deg, #6366f1 0%, #a855f7 100%);
    --bg-color: #0f172a;
    --card-bg: rgba(30, 41, 59, 0.7);
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --border-color: rgba(255, 255, 255, 0.1);
    --accent-color: #38bdf8;
    --danger-color: #ef4444;
    --success-color: #22c55e;
    --input-bg: rgba(15, 23, 42, 0.8);
    --summary-bg: rgba(26, 39, 68, 0.8);
    --badge-pages-bg: rgba(56, 189, 248, 0.12);
    --badge-pages-color: #38bdf8;
}

[data-theme="light"] {
    --bg-color: #f1f5f9;
    --card-bg: rgba(255, 255, 255, 0.85);
    --text-primary: #0f172a;
    --text-secondary: #64748b;
    --border-color: rgba(0, 0, 0, 0.1);
    --input-bg: rgba(241, 245, 249, 0.9);
    --summary-bg: rgba(224, 231, 255, 0.6);
    --badge-pages-bg: rgba(56, 189, 248, 0.15);
    --badge-pages-color: #0284c7;
}

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

body {
    font-family: 'Outfit', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    background-image: 
        radial-gradient(circle at 10% 20%, rgba(99, 102, 241, 0.15) 0%, transparent 40%),
        radial-gradient(circle at 90% 80%, rgba(168, 85, 247, 0.15) 0%, transparent 40%);
}

.container {
    width: 100%;
    max-width: 600px;
    padding: 2rem;
}

.app-card {
    background: var(--card-bg);
    backdrop-filter: blur(12px);
    border: 1px solid var(--border-color);
    border-radius: 24px;
    padding: 2.5rem;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
}

/* ── HEADER ──────────────────────────────────────────────────────── */
.header-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 0.5rem;
}

.theme-toggle {
    background: rgba(255, 255, 255, 0.06);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    width: 38px;
    height: 38px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    font-size: 1.1rem;
    transition: all 0.2s;
    color: var(--text-secondary);
    flex-shrink: 0;
}

.theme-toggle:hover {
    background: rgba(255, 255, 255, 0.12);
    color: var(--text-primary);
}

h1 {
    font-size: 2rem;
    font-weight: 700;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

p.subtitle {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    font-size: 0.95rem;
}

/* ── FILENAME INPUT ──────────────────────────────────────────────── */
.filename-section {
    margin-bottom: 1.5rem;
}

.filename-label {
    display: block;
    font-size: 0.78rem;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: 0.4rem;
    letter-spacing: 0.03em;
    text-transform: uppercase;
}

.filename-input-wrap {
    display: flex;
    align-items: center;
    background: var(--input-bg);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    padding: 0 1rem;
    transition: border-color 0.2s;
}

.filename-input-wrap:focus-within {
    border-color: #6366f1;
}

.filename-input {
    flex: 1;
    background: none;
    border: none;
    outline: none;
    color: var(--text-primary);
    font-family: 'Outfit', sans-serif;
    font-size: 0.95rem;
    padding: 0.75rem 0;
}

.filename-ext {
    color: var(--text-secondary);
    font-size: 0.9rem;
    user-select: none;
}

.upload-area {
    border: 2px dashed var(--border-color);
    border-radius: 16px;
    padding: 3rem 2rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    background: rgba(255, 255, 255, 0.03);
    position: relative;
}

.upload-area:hover, .upload-area.drag-over {
    border-color: var(--accent-color);
    background: rgba(56, 189, 248, 0.05);
}

.upload-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
    display: block;
}

.upload-text-main {
    font-weight: 600;
    display: block;
    margin-bottom: 0.25rem;
}

.upload-text-sub {
    color: var(--text-secondary);
    font-size: 0.85rem;
}

#file-input {
    display: none;
}

.file-list {
    margin-top: 2rem;
    max-height: 300px;
    overflow-y: auto;
    padding-right: 0.5rem;
}

/* Custom Scrollbar */
.file-list::-webkit-scrollbar {
    width: 6px;
}
.file-list::-webkit-scrollbar-track {
    background: transparent;
}
.file-list::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 10px;
}

.file-item {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1rem;
    margin-bottom: 0.75rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    animation: slideIn 0.3s ease-out forwards;
    cursor: grab;
    transition: transform 0.2s, background 0.2s, opacity 0.2s;
}

.file-item.dragging {
    opacity: 0.4;
    cursor: grabbing;
    background: rgba(99, 102, 241, 0.1);
    border-color: var(--accent-color);
}

.file-item:active {
    cursor: grabbing;
}

.file-item:hover {
    background: rgba(255, 255, 255, 0.08);
}

@keyframes slideIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.file-main-info {
    display: flex;
    align-items: center;
    gap: 1rem;
    flex: 1;
}

.reorder-btns {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.reorder-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 2px;
    border-radius: 4px;
    transition: all 0.2s;
    line-height: 1;
}

.reorder-btn:hover {
    background: rgba(255, 255, 255, 0.1);
    color: var(--text-primary);
}

.file-info {
    display: flex;
    flex-direction: column;
}

.file-name {
    font-size: 0.9rem;
    font-weight: 500;
    max-width: 250px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.file-size {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.file-meta {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-top: 0.15rem;
}

.pages-badge {
    font-size: 0.7rem;
    font-weight: 600;
    color: var(--badge-pages-color);
    background: var(--badge-pages-bg);
    border-radius: 5px;
    padding: 1px 6px;
}

.remove-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 50%;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
}

.remove-btn:hover {
    background: rgba(239, 68, 68, 0.1);
    color: var(--danger-color);
}

/* ── SUMMARY BAR ─────────────────────────────────────────────────── */
.summary-bar {
    margin-top: 1.25rem;
    background: var(--summary-bg);
    border: 1px solid rgba(99, 102, 241, 0.2);
    border-radius: 10px;
    padding: 0.6rem 1rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    font-size: 0.82rem;
}

.summary-stats {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 600;
}

.summary-highlight-indigo { color: #818cf8; }
.summary-highlight-accent  { color: var(--accent-color); }
.summary-sep { color: var(--text-secondary); opacity: 0.5; }

.privacy-badge {
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--success-color);
    background: rgba(34, 197, 94, 0.1);
    border-radius: 6px;
    padding: 2px 8px;
}

/* ── PROGRESS BAR ────────────────────────────────────────────────── */
.progress-wrap {
    margin-top: 1rem;
}

.progress-meta {
    display: flex;
    justify-content: space-between;
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-bottom: 0.4rem;
}

#progress-pct {
    font-weight: 600;
    color: var(--accent-color);
}

.progress-track {
    height: 6px;
    background: rgba(255, 255, 255, 0.08);
    border-radius: 4px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, #6366f1, #38bdf8);
    border-radius: 4px;
    transition: width 0.3s ease;
}

.actions {
    margin-top: 1.25rem;
    display: flex;
    gap: 1rem;
}

.btn {
    flex: 1;
    padding: 1rem;
    border-radius: 12px;
    border: none;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.btn-primary {
    background: var(--primary-gradient);
    color: white;
    box-shadow: 0 4px 15px rgba(99, 102, 241, 0.3);
}

.btn-primary:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(99, 102, 241, 0.4);
}

.btn-primary:active:not(:disabled) {
    transform: translateY(0);
}

.btn-primary:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    filter: grayscale(1);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.05);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover:not(:disabled) {
    background: rgba(255, 255, 255, 0.1);
}


.status-message {
    margin-top: 1rem;
    text-align: center;
    font-size: 0.85rem;
    min-height: 1.25rem;
}

.status-success { color: var(--success-color); }
.status-error { color: var(--danger-color); }

/* Draggable handle placeholder if needed later */
.drag-handle {
    cursor: grab;
    margin-right: 0.75rem;
    color: var(--text-secondary);
}