:root {
    --primary: #2563eb;
    --primary-hover: #1d4ed8;
    --accent: #f1f5f9;
    --border: #e2e8f0;
    --border-focus: #93c5fd;
    --text: #0f172a;
    --text-secondary: #64748b;
    --text-muted: #94a3b8;
    --bg: #f8fafc;
    --surface: #ffffff;
    --success: #16a34a;
    --success-bg: #f0fdf4;
    --success-border: #bbf7d0;
    --error: #dc2626;
    --error-bg: #fef2f2;
    --error-border: #fecaca;
    --warning-bg: #fffbeb;
    --warning-border: #fde68a;
    --warning-text: #92400e;
    --radius: 8px;
    --radius-lg: 12px;
    --transition: 0.15s ease;
}

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

body {
    font-family: 'Inter', 'Segoe UI', system-ui, sans-serif;
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
    padding: 32px 16px;
    font-size: 14px;
    line-height: 1.5;
}

.container {
    max-width: 860px;
    margin: 0 auto;
}

.container-wide {
    max-width: 1180px;
}

/* Header / Branding */
.header {
    margin-bottom: 28px;
}

.header-top {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    margin-bottom: 4px;
}

.brand {
    display: flex;
    align-items: center;
    gap: 8px;
    text-decoration: none;
}

.brand-icon {
    font-size: 22px;
    color: var(--primary);
    line-height: 1;
}

.brand-name {
    font-size: 22px;
    font-weight: 800;
    color: var(--text);
    letter-spacing: -0.5px;
}

.tagline {
    color: var(--text-secondary);
    font-size: 13px;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
    justify-content: flex-end;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 12px;
    font-weight: 600;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 6px 10px;
    background: var(--surface);
    transition: border-color var(--transition), color var(--transition), background var(--transition);
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary);
    border-color: var(--border-focus);
    background: #eff6ff;
}

/* Badge */
.badge {
    display: inline-block;
    font-size: 10px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    padding: 2px 7px;
    border-radius: 99px;
    background: var(--accent);
    color: var(--text-secondary);
    border: 1px solid var(--border);
    vertical-align: middle;
    margin-left: 6px;
}

/* Send log */
.send-log {
    max-height: 200px;
    overflow-y: auto;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    background: var(--bg);
    padding: 8px 12px;
    font-size: 12px;
    font-family: 'Courier New', monospace;
}

.log-entry {
    padding: 2px 0;
    color: var(--text-secondary);
}

.log-success { color: var(--success); }
.log-error   { color: var(--error); }
.log-muted   { color: var(--text-muted); }

/* Card / Section */
.section {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 24px;
    margin-bottom: 16px;
}

.section-title {
    font-size: 13px;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 16px;
}

.section h2 {
    font-size: 15px;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 16px;
}

.section h3 {
    font-size: 13px;
    font-weight: 600;
    color: var(--text-secondary);
    margin: 20px 0 12px;
}

.section h3:first-of-type {
    margin-top: 0;
}

/* Info box */
.info-box {
    background: var(--warning-bg);
    border: 1px solid var(--warning-border);
    border-radius: var(--radius);
    padding: 12px 16px;
    margin-bottom: 16px;
    font-size: 13px;
    color: var(--warning-text);
}

.info-box a {
    color: var(--primary);
    text-decoration: underline;
}

code {
    background: var(--accent);
    border: 1px solid var(--border);
    border-radius: 4px;
    padding: 1px 5px;
    font-size: 11px;
    font-family: 'Courier New', monospace;
    color: var(--text);
}

/* Upload areas */
.upload-area {
    border: 1.5px dashed var(--border);
    border-radius: var(--radius);
    padding: 28px 20px;
    text-align: center;
    cursor: pointer;
    transition: border-color var(--transition), background var(--transition);
    background: var(--bg);
    color: var(--text-secondary);
    font-size: 13px;
}

.upload-area:hover {
    border-color: var(--primary);
    background: #eff6ff;
}

.upload-area.dragover {
    border-color: var(--primary);
    background: #eff6ff;
}

.upload-area p {
    margin-bottom: 4px;
}

.upload-area .upload-icon {
    font-size: 24px;
    margin-bottom: 8px;
    display: block;
}

.upload-area .hint {
    color: var(--text-muted);
    font-size: 12px;
}

input[type="file"] {
    display: none;
}

/* Divider */
.divider {
    display: flex;
    align-items: center;
    gap: 12px;
    margin: 20px 0;
    color: var(--text-muted);
    font-size: 12px;
    font-weight: 500;
}

.divider::before,
.divider::after {
    content: '';
    flex: 1;
    height: 1px;
    background: var(--border);
}

/* Textarea */
textarea {
    width: 100%;
    min-height: 120px;
    padding: 10px 12px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-family: 'Courier New', monospace;
    font-size: 13px;
    color: var(--text);
    background: var(--surface);
    resize: vertical;
    transition: border-color var(--transition);
}

textarea:focus {
    outline: none;
    border-color: var(--border-focus);
}

textarea::placeholder {
    color: var(--text-muted);
}

/* Form controls */
.controls {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 12px;
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

label {
    font-size: 12px;
    font-weight: 500;
    color: var(--text-secondary);
}

input[type="number"],
input[type="text"],
select {
    padding: 8px 10px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-size: 13px;
    color: var(--text);
    background: var(--surface);
    transition: border-color var(--transition);
}

input[type="number"]:focus,
input[type="text"]:focus,
select:focus {
    outline: none;
    border-color: var(--border-focus);
}

input[type="color"] {
    padding: 3px 4px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    height: 36px;
    width: 100%;
    cursor: pointer;
    background: var(--surface);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    padding: 9px 18px;
    border: none;
    border-radius: var(--radius);
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    transition: background var(--transition), opacity var(--transition);
    width: 100%;
    margin-top: 16px;
}

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

.btn-primary:hover:not(:disabled) {
    background: var(--primary-hover);
}

.btn-secondary {
    background: var(--accent);
    color: var(--text);
    border: 1px solid var(--border);
}

.btn-secondary:hover:not(:disabled) {
    background: var(--border);
}

.btn:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

/* Alert badges */
.alert {
    padding: 10px 14px;
    border-radius: var(--radius);
    font-size: 13px;
    display: flex;
    align-items: center;
    gap: 8px;
    margin-top: 10px;
}

.alert-success {
    background: var(--success-bg);
    border: 1px solid var(--success-border);
    color: var(--success);
}

.alert-error {
    background: var(--error-bg);
    border: 1px solid var(--error-border);
    color: var(--error);
}

/* Preview */
.preview {
    margin-top: 16px;
    text-align: center;
}

.preview img {
    max-width: 100%;
    border-radius: var(--radius);
    border: 1px solid var(--border);
}

.template-preview {
    max-width: 280px;
    margin-top: 12px;
    border-radius: var(--radius);
    border: 1px solid var(--border);
}

/* Bulk Certificate Editor */
.bulk-upload-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
}

.file-summary {
    margin-top: 8px;
    font-size: 12px;
    color: var(--text-secondary);
    word-break: break-word;
}

.batch-preview-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(112px, 1fr));
    gap: 10px;
    margin-top: 16px;
}

.batch-thumb {
    min-height: 96px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    background: var(--bg);
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

.batch-thumb img {
    width: 100%;
    aspect-ratio: 4 / 3;
    object-fit: cover;
    border-bottom: 1px solid var(--border);
}

.batch-thumb-zip {
    justify-content: center;
    align-items: stretch;
}

.batch-thumb-zip strong {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 64px;
    border-bottom: 1px solid var(--border);
    color: var(--primary);
    font-size: 13px;
    letter-spacing: 0.06em;
}

.batch-thumb span,
.batch-thumb-more {
    padding: 6px 8px;
    font-size: 11px;
    color: var(--text-secondary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.batch-thumb-more {
    align-items: center;
    justify-content: center;
    min-height: 96px;
    font-weight: 600;
    white-space: normal;
}

.bulk-editor-layout {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 330px;
    gap: 20px;
    align-items: start;
}

.canvas-shell {
    min-width: 0;
}

.canvas-stage {
    width: 100%;
    min-height: 360px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    background: var(--bg);
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: auto;
}

.canvas-placeholder {
    color: var(--text-muted);
    font-size: 13px;
}

#editorCanvas {
    display: none;
    width: 100%;
    height: auto;
    cursor: crosshair;
    touch-action: none;
}

.region-panel {
    border-left: 1px solid var(--border);
    padding-left: 20px;
    min-width: 0;
}

.region-panel-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    margin-bottom: 10px;
}

.region-panel .section h3,
.region-panel h3 {
    margin-top: 18px;
}

.btn-inline {
    width: auto;
    margin-top: 0;
    padding: 6px 10px;
}

.region-list {
    display: grid;
    gap: 8px;
    max-height: 190px;
    overflow-y: auto;
    padding-right: 4px;
}

.region-empty {
    padding: 10px 0;
    color: var(--text-muted);
    font-size: 12px;
}

.region-list-item {
    width: 100%;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    background: var(--surface);
    padding: 8px 10px;
    cursor: pointer;
    text-align: left;
    display: grid;
    gap: 2px;
    transition: border-color var(--transition), background var(--transition);
}

.region-list-item:hover,
.region-list-item.selected {
    border-color: var(--border-focus);
    background: #eff6ff;
}

.region-list-item span {
    font-size: 12px;
    color: var(--text-secondary);
}

.region-list-item strong {
    font-size: 12px;
    color: var(--text);
    font-weight: 600;
}

.controls-tight {
    grid-template-columns: repeat(2, minmax(0, 1fr));
}

.textarea-small {
    min-height: 74px;
    font-family: 'Inter', 'Segoe UI', system-ui, sans-serif;
}

.editor-actions {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 10px;
    margin-top: 14px;
}

.editor-actions .btn {
    margin-top: 0;
    padding-left: 10px;
    padding-right: 10px;
}

/* Progress */
.progress {
    margin-top: 16px;
    display: none;
}

.progress-label {
    font-size: 12px;
    color: var(--text-secondary);
    margin-bottom: 6px;
}

.progress-track {
    width: 100%;
    height: 6px;
    background: var(--accent);
    border-radius: 99px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: var(--primary);
    width: 0%;
    transition: width 0.3s ease;
    border-radius: 99px;
}

.status {
    font-size: 13px;
    color: var(--text-secondary);
    margin-top: 8px;
}

/* Scrollbar */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 99px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-muted); }

/* Mode toggle segmented control */
.mode-toggle-group {
    display: inline-flex;
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 4px;
    gap: 4px;
    width: 100%;
}

.mode-toggle-btn {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    padding: 8px 12px;
    font-size: 13px;
    font-weight: 500;
    color: var(--text-secondary);
    background: transparent;
    border: none;
    border-radius: calc(var(--radius) - 2px);
    cursor: pointer;
    transition: all var(--transition);
}

.mode-toggle-btn:hover {
    color: var(--text);
    background: rgba(0, 0, 0, 0.04);
}

.mode-toggle-btn.active {
    background: var(--surface);
    color: var(--primary);
    font-weight: 600;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

/* Responsive */
@media (max-width: 900px) {
    .bulk-editor-layout { grid-template-columns: 1fr; }
    .region-panel { border-left: none; border-top: 1px solid var(--border); padding-left: 0; padding-top: 18px; }
}

@media (max-width: 640px) {
    body { padding: 16px; }
    .controls { grid-template-columns: 1fr 1fr; }
    .mode-toggle-group { flex-direction: column; }
    .header h1 { font-size: 18px; }
    .header-top { align-items: flex-start; flex-direction: column; }
    .nav-links { justify-content: flex-start; }
    .bulk-upload-grid { grid-template-columns: 1fr; }
    .canvas-stage { min-height: 260px; }
    .editor-actions { grid-template-columns: 1fr; }
}