:root {
    --bg-primary: #1a1a1a;
    --bg-secondary: #2d2d2d;
    --bg-tertiary: #404040;
    --border-color: #404040;
    --text-primary: #ffffff;
    --text-secondary: #adb5bd;
    --accent-color: #0d6efd;
    --accent-success: #66BB6A;
    --accent-hover: #0b5ed7;
    --shadow: 0 2px 8px rgba(0,0,0,0.3);
    --shadow-strong: 0 4px 20px rgba(0,0,0,0.4);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg-tertiary);
    color: var(--text-primary);
    overflow-x: hidden;
}

/* App container */
.app-container {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.main-container {
    display: flex;
    flex: 1;
    gap: 20px;
    padding: 20px;
    min-height: calc(100vh - 96px);
}

/* Controls Panel - Sticky sidebar like typescale */
.controls-panel {
    width: 320px;
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 20px;
    height: fit-content;
    position: sticky;
    top: 20px;
}

.control-section {
    margin-bottom: 24px;
}

.control-section:last-child {
    margin-bottom: 0;
}

.section-header h3 {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 16px;
    padding-bottom: 8px;
    border-bottom: 1px solid var(--border-color);
}

/* Form Elements */
.form-group {
    margin-bottom: 16px;
}

.form-group:last-child {
    margin-bottom: 0;
}

.form-group label {
    display: block;
    margin-bottom: 6px;
    font-weight: 500;
    color: var(--text-primary);
    font-size: 14px;
}

/* Checkbox layout wrapper */
.checkbox-wrapper {
    display: flex;
    align-items: center;
    gap: 12px;
}

.checkbox-wrapper input[type="checkbox"] {
    margin: 0;
    width: 20px;
    height: 20px;
    flex-shrink: 0;
}

.checkbox-wrapper label {
    margin: 0;
    font-weight: 500;
    color: var(--text-primary);
}

.form-input, .form-select {
    width: 100%;
    padding: 10px 12px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 14px;
    background: var(--bg-secondary);
    color: var(--text-primary);
    transition: all 0.2s;
}

.form-input:focus, .form-select:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(13, 110, 253, 0.1);
}

.form-select {
    background-image: none;
}

.input-hint {
    font-size: 12px;
    color: var(--text-secondary);
    margin-top: 4px;
}

.form-check-input {
    accent-color: var(--accent-color);
}

.form-check-input:focus {
    box-shadow: 0 0 0 3px rgba(13, 110, 253, 0.1);
}

.form-check-input:checked {
    background-color: var(--accent-color);
    border-color: var(--accent-color);
}

/* Preview Panel */
.preview-panel {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 20px;
    background: var(--bg-secondary);
    padding: 24px;
    border-radius: 12px;
}

.preview-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 24px;
    padding-bottom: 16px;
    border-bottom: 1px solid var(--border-color);
}

.preview-header h3 {
    font-size: 18px;
    font-weight: 600;
    color: var(--text-primary);
}

.preview-info {
    font-size: 13px;
    font-weight: 500;
    color: var(--text-secondary);
    padding: 6px 12px;
    background: var(--bg-secondary);
    border-radius: 6px;
    border: 1px solid var(--border-color);
}

.preview-container {
    flex: 1;
    background: var(--bg-tertiary);
    border: 2px solid var(--border-color);
    border-radius: 12px;
    padding: 0;
    position: relative;
}

/* Text-specific styles */
.text-display {
    width: 100%;
    min-height: 400px;
    padding: 20px;
    border: 2px solid var(--border-color);
    border-radius: 12px;
    background: var(--bg-tertiary);
    color: var(--text-primary);
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    font-size: 15px;
    line-height: 1.6;
    resize: none;
    overflow-y: auto;
    white-space: pre-wrap;
    word-wrap: break-word;
    cursor: text;
    user-select: text;
    transition: all 0.2s ease;
}

.text-display:focus,
.text-display:focus-within {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(13, 110, 253, 0.15);
}

.text-stats {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 20px;
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    margin-bottom: 16px;
    font-size: 13px;
    font-weight: 600;
    color: var(--text-secondary);
    font-family: 'Courier New', monospace;
}

.stats-left {
    display: flex;
    gap: 24px;
}

.stats-right {
    display: flex;
    align-items: center;
}

.stat-item {
    display: flex;
    align-items: center;
    gap: 6px;
    white-space: nowrap;
}

.stat-value {
    color: var(--text-primary);
    font-weight: 700;
}

/* Buttons */
.btn {
    padding: 10px 16px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 600;
    transition: all 0.2s;
    background: var(--bg-secondary);
    color: var(--text-primary);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.btn-primary {
    background: var(--accent-color);
    color: white;
    border-color: var(--accent-color);
}

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

.btn-secondary {
    background: var(--bg-primary);
    color: var(--text-primary);
    border-color: var(--border-color);
}

.btn-secondary:hover {
    background: var(--bg-tertiary);
    border-color: var(--accent-color);
}

.btn-copy {
    background: var(--accent-success);
    color: white;
    border-color: var(--accent-success);
}

.btn-copy:hover {
    background: #5aa65a;
    border-color: #5aa65a;
}

.btn-sm {
    padding: 6px 10px;
    font-size: 12px;
    min-width: 32px;
}

.btn-generate {
    width: 100%;
    padding: 12px;
    font-size: 16px;
    font-weight: 600;
}

.preview-actions {
    display: flex;
    gap: 12px;
    align-items: center;
    justify-content: flex-start;
}

/* Font size controls */
.font-size-controls {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-left: auto;
}

#fontSizeDisplay {
    font-size: 12px;
    color: var(--text-secondary);
    font-family: 'Courier New', monospace;
    min-width: 32px;
    text-align: center;
}

/* Visually hidden for screen readers */
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0,0,0,0);
    white-space: nowrap;
    border: 0;
}

/* Responsive */
@media (max-width: 1024px) {
    .main-container {
        flex-direction: column;
        gap: 16px;
        padding: 16px;
    }

    .controls-panel {
        width: 100%;
        position: static;
    }
}

@media (max-width: 968px) {
    .text-stats {
        flex-direction: column;
        gap: 12px;
        text-align: center;
        padding: 16px;
    }

    .stats-left {
        gap: 16px;
    }

    .stats-right {
        justify-content: center;
    }

    .text-display {
        min-height: 300px;
        font-size: 15px;
    }

    .preview-actions {
        flex-direction: column;
        align-items: stretch;
        gap: 8px;
    }

    .font-size-controls {
        justify-content: center;
        margin-left: 0;
        order: -1;
    }
}

@media (max-width: 768px) {
    .main-container {
        padding: 12px;
    }
}

@media (max-width: 640px) {
    .text-display {
        min-height: 250px;
        padding: 16px;
        font-size: 15px;
    }

    .stats-left {
        flex-direction: column;
        gap: 8px;
    }

    .stat-item {
        justify-content: center;
    }
}