:root {
    --bg-color: #0f1115;
    --surface-color: #1a1d23;
    --surface-hover: #242830;
    --primary-color: #646cff;
    --primary-hover: #747bff;
    --text-primary: #ffffff;
    --text-secondary: #a1a1aa;
    --border-color: #2e323a;
    --accent-gradient: linear-gradient(135deg, #646cff 0%, #9f64ff 100%);

    --font-ui: 'Inter', system-ui, -apple-system, sans-serif;
}

.light-theme {
    --bg-color: #f8f9fa;
    --surface-color: #ffffff;
    --surface-hover: #f1f3f5;
    --primary-color: #4f46e5;
    --primary-hover: #4338ca;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --border-color: #e5e7eb;
}

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

body {
    font-family: var(--font-ui);
    background-color: var(--bg-color);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.app-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 2rem;
    width: 100%;
    height: 100vh;
    display: flex;
    flex-direction: column;
}

header {
    text-align: center;
    margin-bottom: 2rem;
    position: relative;
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 0.5rem;
}

header h1 {
    font-size: 1.5rem;
    /* 2.5rem; */
    font-weight: 700;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 0;
    padding-left: 25px;
}

header p {
    color: var(--text-secondary);
}

/* Drop Zone */
.drop-zone {
    border: 2px dashed var(--border-color);
    border-radius: 1rem;
    padding: 4rem 2rem;
    text-align: center;
    transition: all 0.3s ease;
    cursor: pointer;
    background: var(--surface-color);
}

.drop-zone:hover,
.drop-zone.drag-over {
    border-color: var(--primary-color);
    background: var(--surface-hover);
}

.drop-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
    color: var(--text-secondary);
}

/* Workspace */
.workspace {
    display: grid;
    grid-template-columns: 300px 1fr;
    grid-template-rows: 1fr;
    /* Force full height */
    gap: 2rem;
    flex: 1;
    min-height: 600px;
    /* default:0 */
    /* For scrolling */
}

.workspace.hidden {
    display: none;
}

/* Controls Panel */
.controls-panel {
    background: var(--surface-color);
    border-radius: 1rem;
    padding: 1.5rem;
    border: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    overflow-y: auto;
}

.panel-header {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.panel-header h2 {
    font-size: 1rem;
    /* 1.25rem */
    margin-bottom: 0;
}

.font-name {
    font-size: 0.875rem;
    color: var(--text-secondary);
    word-break: break-all;
}

/* Collapsible Sections */
.collapsible .section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    user-select: none;
}

.collapsible .section-header:hover h3 {
    color: var(--text-primary);
}

.collapsible .section-header:hover .chevron {
    color: var(--text-primary);
}

.chevron {
    transition: transform 0.3s ease;
    color: var(--text-secondary);
}

.collapsible.collapsed .chevron {
    transform: rotate(-90deg);
}

.section-content {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    overflow: hidden;
    transition: all 0.3s ease;
    max-height: 500px;
    /* Arbitrary large value */
    opacity: 1;
}

.collapsible.collapsed .section-content {
    max-height: 0;
    opacity: 0;
    margin: 0;
    gap: 0;
}

.collapsible.collapsed {
    padding-bottom: 8px;
}

/* Typography Controls */
.typography-controls {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.typography-controls h3 {
    font-size: 0.875rem;
    color: var(--text-secondary);
    transition: color 0.2s;
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.control-group label {
    font-size: 0.75rem;
    font-weight: 500;
}

.toggle-group {
    display: flex;
    background: var(--bg-color);
    padding: 2px;
    border-radius: 0.5rem;
    border: 1px solid var(--border-color);
}

.toggle-btn {
    flex: 1;
    background: none;
    border: none;
    color: var(--text-secondary);
    padding: 0.5rem;
    cursor: pointer;
    border-radius: 0.25rem;
    font-size: 0.75rem;
    transition: all 0.2s;
}

.toggle-btn:hover {
    color: var(--text-primary);
}

.toggle-btn.active {
    background: var(--surface-hover);
    color: var(--text-primary);
    font-weight: 500;
}


/* OpenType Controls */
.opentype-controls {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.opentype-controls h3 {
    font-size: 0.875rem;
    color: var(--text-secondary);
    transition: color 0.2s;
}

.opentype-controls.hidden {
    display: none;
}

.features-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
    gap: 0.5rem;
}

.feature-checkbox {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.75rem;
    color: var(--text-secondary);
    cursor: pointer;
    user-select: none;
}

.feature-checkbox:hover {
    color: var(--text-primary);
}

.feature-checkbox input {
    accent-color: var(--primary-color);
}

.axes-container {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.axis-control {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.axis-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.875rem;
    font-weight: 500;
}

.axis-label-group {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.play-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 2px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    transition: all 0.2s;
}

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

.play-btn.playing {
    color: var(--primary-color);
}

.axis-value {
    color: var(--primary-color);
    font-family: monospace;
}

input[type="range"] {
    width: 100%;
    height: 4px;
    background: var(--border-color);
    border-radius: 2px;
    appearance: none;
    outline: none;
    margin: 0.5rem 0;
}

input[type="range"]::-webkit-slider-thumb {
    appearance: none;
    width: 16px;
    height: 16px;
    background: var(--primary-color);
    border-radius: 50%;
    cursor: pointer;
    transition: transform 0.1s;
}

input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
}

/* CSS Output */
.css-output-container h3 {
    font-size: 0.875rem;
    margin-bottom: 0.5rem;
    color: var(--text-secondary);
}

.css-output-container {
    margin-top: auto;
}

.code-block {
    background: #000;
    padding: 1rem;
    border-radius: 0.5rem;
    font-family: monospace;
    font-size: 0.875rem;
    color: #a5f3fc;
    position: relative;
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 0.5rem;
}

.icon-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 4px;
    border-radius: 4px;
    transition: color 0.2s;
}

.icon-btn:hover {
    color: var(--text-primary);
    background: var(--surface-hover);
}

/* Preview Panel */
.preview-panel {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    min-height: 0;
}

.preview-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.5rem 0;
}

.preview-controls {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

#font-size-input {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 0.25rem 0.5rem;
    border-radius: 0.25rem;
    width: 60px;
}

.sample-controls {
    display: flex;
    background: var(--surface-color);
    border-radius: 0.5rem;
    padding: 2px;
    margin-right: 1rem;
}

.sample-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    padding: 0.25rem 0.75rem;
    cursor: pointer;
    border-radius: 0.25rem;
    font-size: 0.75rem;
    font-weight: 600;
    transition: all 0.2s;
}

.sample-btn:hover {
    color: var(--text-primary);
}

.align-controls {
    display: flex;
    background: var(--surface-color);
    border-radius: 0.5rem;
    padding: 2px;
}

.align-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    padding: 0.5rem 1rem;
    cursor: pointer;
    border-radius: 0.25rem;
    font-size: 0.875rem;
    transition: all 0.2s;
}

.align-btn:hover {
    color: var(--text-primary);
}

.align-btn.active {
    background: var(--surface-hover);
    color: var(--text-primary);
}

.preview-area {
    flex: 1;
    background: var(--surface-color);
    border-radius: 1rem;
    border: 1px solid var(--border-color);
    overflow: hidden;
    display: flex;
}

#preview-text {
    width: 100%;
    height: 100%;
    background: transparent;
    border: none;
    color: var(--text-primary);
    padding: 2rem;
    resize: none;
    outline: none;
    font-size: 64px;
    line-height: 1.2;
    text-align: left;
}

.vertical-mode {
    writing-mode: vertical-rl;
    text-orientation: upright;
    /* Or mixed, depending on preference. Upright is good for pure Japanese. */
    overflow-x: auto;
    overflow-y: hidden;
}

/* Drag Overlay */
.drag-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(15, 17, 21, 0.9);
    z-index: 1000;
    display: flex;
    justify-content: center;
    align-items: center;
    opacity: 1;
    transition: opacity 0.2s;
    backdrop-filter: blur(4px);
}

.drag-overlay.hidden {
    opacity: 0;
    pointer-events: none;
}

.overlay-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.5rem;
    color: var(--primary-color);
}

.overlay-content h2 {
    font-size: 2rem;
    color: var(--text-primary);
}

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

/* Responsive */
@media (max-width: 768px) {
    .workspace {
        grid-template-columns: 1fr;
        grid-template-rows: auto 1fr;
    }

    .app-container {
        padding: 1rem;
        height: auto;
    }
}

/* Footer */
footer {
    margin-top: auto;
    padding-top: 20px;
    padding-bottom: 2rem;
    /* border-top: 1px solid var(--border-color); */
    text-align: center;
    font-size: 0.75rem;
    /* 12px */
    line-height: 1.4rem;
    color: var(--text-secondary);
}

footer a {
    color: inherit;
    text-decoration: none;
}

footer a:hover {
    text-decoration: underline;
    color: var(--text-primary);
}

.copyright {
    margin-top: 10px;
}