:root {
    --bg-dark: #0f172a;
    --bg-panel: #1e293b;
    --bg-hover: #334155;
    --primary: #10b981;
    /* Moss Green-ish */
    --primary-hover: #059669;
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --border: #334155;
    --danger: #ef4444;

    --radius: 12px;
    --spacing: 16px;
    --font-family: 'Inter', system-ui, -apple-system, sans-serif;
}

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

body {
    background-color: var(--bg-dark);
    color: var(--text-main);
    font-family: var(--font-family);
    min-height: 100vh;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 6px;
    height: 6px;
}

::-webkit-scrollbar-thumb {
    background: var(--border);
    border-radius: 3px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

/* Layout */
header {
    height: 60px;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 var(--spacing);
    background-color: var(--bg-panel);
}

.brand {
    font-size: 1.25rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 12px;
    color: var(--primary);
}

.brand-logo {
    width: 32px;
    height: 32px;
    image-rendering: pixelated;
}

main {
    flex: 1;
    display: flex;
    min-height: calc(100vh - 60px);
    padding: var(--spacing);
    gap: var(--spacing);
}

/* Panels */
.panel {
    background-color: var(--bg-panel);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.panel-header {
    padding: 12px;
    border-bottom: 1px solid var(--border);
    font-weight: 600;
    font-size: 0.9rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

/* Left Sidebar (Library) */
.library-panel {
    width: 320px;
    flex-shrink: 0;
}

.library-tabs {
    display: flex;
    padding: 8px;
    gap: 8px;
    background: var(--bg-dark);
    margin: 8px;
    border-radius: 8px;
}

.tab-btn {
    flex: 1;
    background: transparent;
    border: none;
    color: var(--text-muted);
    padding: 6px;
    cursor: pointer;
    border-radius: 6px;
    font-size: 0.85rem;
    transition: all 0.2s;
}

.tab-btn.active {
    background: var(--bg-panel);
    color: var(--text-main);
    font-weight: bold;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
}

.library-grid {
    flex: 1;
    overflow-y: auto;
    padding: 8px;
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 8px;
    align-content: start;
}

.library-item {
    aspect-ratio: 1;
    background: var(--bg-dark);
    border: 1px solid var(--border);
    border-radius: 6px;
    cursor: pointer;
    position: relative;
    overflow: hidden;
    transition: border-color 0.2s;
}

.library-item:hover {
    border-color: var(--text-muted);
}

.library-item.selected {
    border-color: var(--primary);
    box-shadow: 0 0 0 2px var(--primary-hover);
}

.library-item canvas {
    width: 100%;
    height: 100%;
    object-fit: contain;
    image-rendering: pixelated;
}

.btn-delete {
    position: absolute;
    top: 2px;
    right: 2px;
    width: 16px;
    height: 16px;
    background: var(--danger);
    color: white;
    border: none;
    border-radius: 50%;
    font-size: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    opacity: 0;
    transition: opacity 0.2s;
}

.library-item:hover .btn-delete {
    opacity: 1;
}

/* Center Workspace (Canvas) */
.workspace-panel {
    flex: 1;
    display: flex;
    flex-direction: column;
}

.canvas-container {
    flex: 1;
    background: #111;
    position: relative;
    overflow: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
    /* Grid Pattern */
    background-image: linear-gradient(#1a1a1a 1px, transparent 1px),
        linear-gradient(90deg, #1a1a1a 1px, transparent 1px);
    background-size: 20px 20px;
}

.canvas-container canvas {
    width: 100%;
    height: 100%;
    display: block;
    image-rendering: pixelated;
    touch-action: none;
}

/* Right Sidebar (Controls) */
.controls-panel {
    width: 280px;
    flex-shrink: 0;
    padding: 12px;
    gap: 16px;
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.control-label {
    font-size: 0.8rem;
    color: var(--text-muted);
    font-weight: 600;
}

.btn {
    background: var(--primary);
    color: white;
    border: none;
    padding: 10px;
    border-radius: 6px;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    transition: background 0.2s;
}

.btn:hover {
    background: var(--primary-hover);
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn-secondary {
    background: var(--bg-hover);
    color: var(--text-main);
}

.btn-secondary:hover {
    background: #475569;
}

input[type="range"] {
    width: 100%;
    accent-color: var(--primary);
}

input[type="text"],
input[type="file"],
select {
    width: 100%;
    padding: 8px;
    border-radius: 6px;
    border: 1px solid var(--border);
    background: var(--bg-dark);
    color: var(--text-main);
    font-size: 0.9rem;
}

select {
    cursor: pointer;
    appearance: none;
    background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 20 20'%3e%3cpath stroke='%2394a3b8' stroke-linecap='round' stroke-linejoin='round' stroke-width='1.5' d='M6 8l4 4 4-4'/%3e%3c/svg%3e");
    background-position: right 0.5rem center;
    background-repeat: no-repeat;
    background-size: 1.5em 1.5em;
    padding-right: 2.5rem;
}

input[type="file"]::file-selector-button {
    background: var(--bg-hover);
    color: var(--text-main);
    border: none;
    padding: 4px 8px;
    border-radius: 4px;
    margin-right: 8px;
    cursor: pointer;
}

/* Modal */
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(4px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.2s;
}

.modal-overlay.open {
    opacity: 1;
    pointer-events: auto;
}

.modal-content {
    background: var(--bg-panel);
    width: 90%;
    max-width: 800px;
    max-height: 90vh;
    border-radius: var(--radius);
    border: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    overflow: hidden;
    transform: scale(0.95);
    transition: transform 0.2s;
}

.modal-overlay.open .modal-content {
    transform: scale(1);
}

.modal-body {
    padding: 20px;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.preview-box {
    height: 200px;
    background: var(--bg-dark);
    border: 1px dashed var(--border);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 10px;
}

.preview-box img {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
    image-rendering: pixelated;
}

/* Toast/Notification */
.toast {
    position: fixed;
    bottom: 20px;
    right: 20px;
    padding: 12px 20px;
    background: var(--bg-hover);
    border-left: 4px solid var(--primary);
    border-radius: 6px;
    color: white;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    transform: translateY(100px);
    transition: transform 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    z-index: 200;
}

.toast.show {
    transform: translateY(0);
}

/* Utilities */
.hidden {
    display: none !important;
}

.flex {
    display: flex;
}

.gap-2 {
    gap: 8px;
}

.col {
    flex-direction: column;
}

.row {
    flex-direction: row;
}

.items-center {
    align-items: center;
}

.justify-between {
    justify-content: space-between;
}

.text-sm {
    font-size: 0.85rem;
}

.text-xs {
    font-size: 0.75rem;
}

/* Background detect controls */
.btn-xs {
    padding: 4px 8px;
    font-size: 0.75rem;
}

.bg-detect {
    margin-top: 8px;
    padding: 8px;
    border: 1px dashed var(--border);
    border-radius: 8px;
    background: rgba(15, 23, 42, 0.35);
    display: grid;
    grid-template-columns: 1fr 120px;
    gap: 10px;
    align-items: stretch;
}

.bg-detect-main {
    display: flex;
    flex-direction: column;
    gap: 8px;
    min-width: 0;
}

.bg-detect-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 8px;
}

.bg-detect-status {
    display: flex;
    align-items: center;
    gap: 8px;
}

.badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 2px 8px;
    border-radius: 999px;
    border: 1px solid var(--border);
    background: var(--bg-panel);
    color: var(--text-muted);
    font-size: 0.75rem;
    line-height: 1.2;
}

.badge-auto {
    color: var(--text-muted);
}

.badge-manual {
    border-color: var(--primary);
    color: var(--text-main);
    background: rgba(16, 185, 129, 0.12);
}

.badge-picking {
    border-color: #f59e0b;
    color: #fef3c7;
    background: rgba(245, 158, 11, 0.15);
}

.bg-detect-value {
    display: flex;
    align-items: center;
    gap: 8px;
}

.bg-swatch {
    width: 16px;
    height: 16px;
    border-radius: 6px;
    border: 1px solid var(--border);
    display: inline-block;
}

.bg-hex {
    font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
    color: var(--text-main);
    font-size: 0.75rem;
}

.bg-swatch-card {
    border-radius: 10px;
    border: 1px solid var(--border);
    overflow: hidden;
    position: relative;
    min-height: 64px;
}

.bg-swatch-card-hex {
    position: absolute;
    right: 6px;
    bottom: 6px;
    padding: 2px 6px;
    border-radius: 8px;
    background: rgba(0, 0, 0, 0.55);
    color: #ffffff;
    font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
    font-size: 0.75rem;
    line-height: 1.2;
    user-select: text;
}

.bg-detect-actions {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
}

@media (max-width: 520px) {
    .bg-detect {
        grid-template-columns: 1fr;
    }

    .bg-swatch-card {
        min-height: 56px;
    }
}

/* Custom frame list */
.custom-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(72px, 1fr));
    gap: 8px;
    max-height: 220px;
    overflow-y: auto;
    padding: 6px;
    border: 1px dashed var(--border);
    border-radius: 8px;
    background: var(--bg-dark);
}

.custom-item {
    position: relative;
    background: var(--bg-panel);
    border: 1px solid var(--border);
    border-radius: 6px;
    padding: 4px;
    display: flex;
    align-items: center;
    justify-content: center;
    height: 72px;
    cursor: grab;
}

.custom-item.dragging {
    opacity: 0.6;
}

.custom-thumb {
    max-width: 100%;
    max-height: 100%;
    image-rendering: pixelated;
}

.custom-remove {
    position: absolute;
    top: 4px;
    right: 4px;
    width: 16px;
    height: 16px;
    border: none;
    background: var(--danger);
    color: #fff;
    border-radius: 4px;
    cursor: pointer;
    font-size: 12px;
    line-height: 14px;
    padding: 0;
}

/* Tutorial Section */
.tutorial-section {
    background: #0b1120;
    /* Slightly darker than bg-dark */
    padding: 40px var(--spacing);
    border-top: 1px solid var(--border);
}

.nano-header {
    text-align: center;
    margin-bottom: 40px;
}

/* Header specific overrides */
header .form-select {
    width: auto;
    padding-top: 6px;
    padding-bottom: 6px;
    font-size: 0.85rem;
    border-color: var(--border);
    background-color: var(--bg-dark);
}

.nano-header h2 {
    color: var(--primary);
    font-size: 2rem;
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
}

.nano-header p {
    color: var(--text-muted);
    font-size: 1.1rem;
}

.nano-steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
    max-width: 1200px;
    margin: 0 auto;
}

.step-card {
    background: var(--bg-panel);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    transition: transform 0.2s, box-shadow 0.2s;
    height: 100%;
    display: flex;
    flex-direction: column;
}

.step-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px -5px rgba(0, 0, 0, 0.3);
    border-color: var(--primary);
}

.step-card img {
    width: 100%;
    aspect-ratio: 16/10;
    object-fit: cover;
    border-bottom: 1px solid var(--border);
    background: #000;
}

.step-content {
    padding: 24px;
    flex: 1;
    display: flex;
    flex-direction: column;
}

.step-content h3 {
    color: var(--primary);
    margin-bottom: 12px;
    font-size: 1.25rem;
}

.step-content p {
    color: var(--text-muted);
    font-size: 0.95rem;
    line-height: 1.6;
}