/**
 * Frequency to Note Converter - Design System & Styling
 * 
 * Modern, responsive, accessible interface with premium visual polish.
 * Uses CSS variables for consistent theming across the plugin ecosystem.
 */

/* ============================================================================
   CSS VARIABLES - Design System
   ============================================================================ */

:root {
	/* Colors */
	--ftnc-color-primary: #4f46e5;
	--ftnc-color-primary-hover: #4338ca;
	--ftnc-color-primary-light: #eef2ff;
	--ftnc-color-secondary: #6b7280;
	--ftnc-color-secondary-light: #f3f4f6;
	--ftnc-color-success: #10b981;
	--ftnc-color-success-light: #ecfdf5;
	--ftnc-color-warning: #f59e0b;
	--ftnc-color-warning-light: #fffbeb;
	--ftnc-color-error: #ef4444;
	--ftnc-color-error-light: #fef2f2;
	--ftnc-color-text-primary: #111827;
	--ftnc-color-text-secondary: #6b7280;
	--ftnc-color-text-tertiary: #9ca3af;
	--ftnc-color-border: #e5e7eb;
	--ftnc-color-border-light: #f3f4f6;
	--ftnc-color-background: #ffffff;
	--ftnc-color-background-alt: #f9fafb;

	/* Typography */
	--ftnc-font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
	--ftnc-font-size-xs: 12px;
	--ftnc-font-size-sm: 14px;
	--ftnc-font-size-base: 16px;
	--ftnc-font-size-lg: 18px;
	--ftnc-font-size-xl: 24px;
	--ftnc-font-size-2xl: 32px;
	--ftnc-font-weight-normal: 400;
	--ftnc-font-weight-medium: 500;
	--ftnc-font-weight-semibold: 600;
	--ftnc-font-weight-bold: 700;
	--ftnc-line-height-tight: 1.3;
	--ftnc-line-height-normal: 1.5;
	--ftnc-line-height-relaxed: 1.75;

	/* Spacing */
	--ftnc-space-xs: 4px;
	--ftnc-space-sm: 8px;
	--ftnc-space-md: 16px;
	--ftnc-space-lg: 24px;
	--ftnc-space-xl: 32px;
	--ftnc-space-2xl: 48px;

	/* Border Radius */
	--ftnc-radius-sm: 4px;
	--ftnc-radius-md: 8px;
	--ftnc-radius-lg: 12px;
	--ftnc-radius-full: 999px;

	/* Shadows */
	--ftnc-shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
	--ftnc-shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
	--ftnc-shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
	--ftnc-shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);

	/* Transitions */
	--ftnc-transition-fast: 150ms ease-in-out;
	--ftnc-transition-normal: 250ms ease-in-out;

	/* Z-index */
	--ftnc-z-index-dropdown: 10;
	--ftnc-z-index-tooltip: 20;
}

/* ============================================================================
   GLOBAL & RESET
   ============================================================================ */

.ftnc-converter {
	font-family: var(--ftnc-font-family);
	color: var(--ftnc-color-text-primary);
	background-color: var(--ftnc-color-background);
	font-size: var(--ftnc-font-size-base);
	line-height: var(--ftnc-line-height-normal);
	-webkit-font-smoothing: antialiased;
	-moz-osx-font-smoothing: grayscale;
	box-sizing: border-box;
}

.ftnc-converter *,
.ftnc-converter *::before,
.ftnc-converter *::after {
	box-sizing: border-box;
}

/* ============================================================================
   CONTAINER
   ============================================================================ */

.ftnc-container {
	max-width: 800px;
	margin: 0 auto;
	padding: var(--ftnc-space-lg);
}

@media (max-width: 640px) {
	.ftnc-container {
		padding: var(--ftnc-space-md);
	}
}

/* ============================================================================
   CONVERTER SECTION
   ============================================================================ */

.ftnc-converter-section {
	background: var(--ftnc-color-background);
	border: 1px solid var(--ftnc-color-border);
	border-radius: var(--ftnc-radius-lg);
	padding: var(--ftnc-space-xl);
	margin-bottom: var(--ftnc-space-2xl);
	box-shadow: var(--ftnc-shadow-md);
}

@media (max-width: 640px) {
	.ftnc-converter-section {
		padding: var(--ftnc-space-lg);
	}
}

/* ============================================================================
   INPUT GROUP
   ============================================================================ */

.ftnc-input-group {
	display: flex;
	flex-direction: column;
	gap: var(--ftnc-space-lg);
	margin-bottom: var(--ftnc-space-lg);
}

.ftnc-input-wrapper {
	display: flex;
	flex-direction: column;
	gap: var(--ftnc-space-sm);
}

.ftnc-label {
	font-size: var(--ftnc-font-size-sm);
	font-weight: var(--ftnc-font-weight-semibold);
	color: var(--ftnc-color-text-primary);
	text-transform: uppercase;
	letter-spacing: 0.5px;
	display: block;
}

/* Separator */
.ftnc-input-separator {
	display: flex;
	align-items: center;
	justify-content: center;
	gap: var(--ftnc-space-md);
	color: var(--ftnc-color-text-tertiary);
	font-size: var(--ftnc-font-size-sm);
	margin: var(--ftnc-space-sm) 0;
}

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

/* ============================================================================
   FORM INPUTS
   ============================================================================ */

.ftnc-input-field {
	position: relative;
	display: flex;
	align-items: center;
}

.ftnc-input,
.ftnc-select {
	width: 100%;
	min-height: 48px;
	padding: 12px 16px;
	font-size: var(--ftnc-font-size-base);
	font-family: var(--ftnc-font-family);
	color: var(--ftnc-color-text-primary);
	background-color: var(--ftnc-color-background);
	border: 1px solid var(--ftnc-color-border);
	border-radius: var(--ftnc-radius-md);
	transition: all var(--ftnc-transition-fast);
	-webkit-appearance: none;
	appearance: none;
}

.ftnc-input::placeholder {
	color: var(--ftnc-color-text-tertiary);
}

.ftnc-input:focus,
.ftnc-select:focus {
	outline: none;
	border-color: var(--ftnc-color-primary);
	box-shadow: 0 0 0 3px var(--ftnc-color-primary-light);
}

.ftnc-input:disabled,
.ftnc-select:disabled {
	background-color: var(--ftnc-color-background-alt);
	color: var(--ftnc-color-text-tertiary);
	cursor: not-allowed;
	opacity: 0.6;
}

/* Input with unit suffix */
.ftnc-input-unit {
	position: absolute;
	right: 16px;
	font-size: var(--ftnc-font-size-sm);
	color: var(--ftnc-color-text-secondary);
	font-weight: var(--ftnc-font-weight-medium);
	pointer-events: none;
}

/* Select styling */
.ftnc-select {
	background-image: url("data:image/svg+xml;charset=UTF-8,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%236b7280' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3e%3cpolyline points='6 9 12 15 18 9'%3e%3c/polyline%3e%3c/svg%3e");
	background-repeat: no-repeat;
	background-position: right 12px center;
	background-size: 20px;
	padding-right: 40px;
	cursor: pointer;
}

/* Flex layout for note and octave selects */
.ftnc-input-flex {
	display: grid;
	grid-template-columns: 2fr 1fr;
	gap: var(--ftnc-space-md);
}

@media (max-width: 640px) {
	.ftnc-input-flex {
		grid-template-columns: 1fr;
	}
}

/* Help text */
.ftnc-help-text {
	font-size: var(--ftnc-font-size-xs);
	color: var(--ftnc-color-text-tertiary);
	line-height: var(--ftnc-line-height-normal);
}

/* ============================================================================
   TUNING CONTROL
   ============================================================================ */

.ftnc-tuning-control {
	display: flex;
	flex-direction: column;
	gap: var(--ftnc-space-sm);
	padding: var(--ftnc-space-lg);
	background-color: var(--ftnc-color-background-alt);
	border-radius: var(--ftnc-radius-md);
	border: 1px solid var(--ftnc-color-border);
}

.ftnc-tuning-select {
	font-size: var(--ftnc-font-size-sm);
}

/* ============================================================================
   BUTTONS
   ============================================================================ */

.ftnc-button-group {
	display: flex;
	gap: var(--ftnc-space-md);
	margin-top: var(--ftnc-space-xl);
}

.ftnc-button {
	min-height: 48px;
	padding: 12px 24px;
	font-size: var(--ftnc-font-size-base);
	font-weight: var(--ftnc-font-weight-semibold);
	border: none;
	border-radius: var(--ftnc-radius-md);
	cursor: pointer;
	transition: all var(--ftnc-transition-fast);
	display: inline-flex;
	align-items: center;
	justify-content: center;
	gap: var(--ftnc-space-sm);
	text-decoration: none;
	-webkit-user-select: none;
	user-select: none;
}

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

/* Primary Button */
.ftnc-button-primary {
	background-color: var(--ftnc-color-primary);
	color: white;
	flex: 1;
}

.ftnc-button-primary:hover:not(:disabled) {
	background-color: var(--ftnc-color-primary-hover);
	box-shadow: var(--ftnc-shadow-md);
	transform: translateY(-1px);
}

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

.ftnc-button-primary:focus {
	outline: none;
	box-shadow: 0 0 0 3px var(--ftnc-color-primary-light);
}

/* Secondary Button */
.ftnc-button-secondary {
	background-color: var(--ftnc-color-secondary-light);
	color: var(--ftnc-color-text-primary);
	flex: 0 0 auto;
}

.ftnc-button-secondary:hover:not(:disabled) {
	background-color: var(--ftnc-color-border);
	box-shadow: var(--ftnc-shadow-sm);
}

.ftnc-button-secondary:focus {
	outline: none;
	box-shadow: 0 0 0 3px var(--ftnc-color-primary-light);
}

/* Copy Button (small variant) */
.ftnc-copy-button {
	background-color: var(--ftnc-color-secondary-light);
	color: var(--ftnc-color-text-secondary);
	border: none;
	border-radius: var(--ftnc-radius-sm);
	padding: 6px 12px;
	font-size: var(--ftnc-font-size-xs);
	font-weight: var(--ftnc-font-weight-medium);
	cursor: pointer;
	transition: all var(--ftnc-transition-fast);
	white-space: nowrap;
}

.ftnc-copy-button:hover {
	background-color: var(--ftnc-color-success);
	color: white;
}

.ftnc-copy-button:focus {
	outline: none;
	box-shadow: 0 0 0 2px var(--ftnc-color-primary-light);
}

/* Responsive buttons */
@media (max-width: 640px) {
	.ftnc-button-group {
		flex-direction: column;
	}

	.ftnc-button {
		width: 100%;
		flex: 1;
	}

	.ftnc-button-secondary {
		flex: 1;
	}
}

/* ============================================================================
   RESULTS SECTION
   ============================================================================ */

.ftnc-results-section {
	margin: var(--ftnc-space-2xl) 0;
}

.ftnc-results-card {
	background: linear-gradient(135deg, var(--ftnc-color-primary-light) 0%, var(--ftnc-color-background) 100%);
	border: 1px solid var(--ftnc-color-primary);
	border-radius: var(--ftnc-radius-lg);
	padding: var(--ftnc-space-xl);
	box-shadow: var(--ftnc-shadow-lg);
}

@media (max-width: 640px) {
	.ftnc-results-card {
		padding: var(--ftnc-space-lg);
	}
}

/* Primary Result */
.ftnc-result-primary {
	text-align: center;
	margin-bottom: var(--ftnc-space-xl);
	padding-bottom: var(--ftnc-space-lg);
	border-bottom: 2px solid var(--ftnc-color-primary);
}

.ftnc-result-label {
	font-size: var(--ftnc-font-size-sm);
	font-weight: var(--ftnc-font-weight-semibold);
	color: var(--ftnc-color-text-secondary);
	text-transform: uppercase;
	letter-spacing: 0.5px;
	margin-bottom: var(--ftnc-space-sm);
	display: block;
}

.ftnc-note-display {
	font-size: var(--ftnc-font-size-2xl);
	font-weight: var(--ftnc-font-weight-bold);
	color: var(--ftnc-color-primary);
	line-height: 1;
}

.ftnc-result-value {
	font-size: var(--ftnc-font-size-xl);
	font-weight: var(--ftnc-font-weight-semibold);
	color: var(--ftnc-color-text-primary);
}

/* Results Grid */
.ftnc-results-grid {
	display: grid;
	grid-template-columns: repeat(2, 1fr);
	gap: var(--ftnc-space-lg);
	margin-bottom: var(--ftnc-space-lg);
}

@media (max-width: 640px) {
	.ftnc-results-grid {
		grid-template-columns: 1fr;
	}
}

.ftnc-result-item {
	display: flex;
	flex-direction: column;
	gap: var(--ftnc-space-sm);
	padding: var(--ftnc-space-md);
	background-color: var(--ftnc-color-background);
	border-radius: var(--ftnc-radius-md);
	border: 1px solid var(--ftnc-color-border-light);
}

.ftnc-result-item .ftnc-result-label {
	margin: 0;
	font-size: var(--ftnc-font-size-xs);
}

.ftnc-result-item .ftnc-result-value {
	font-size: var(--ftnc-font-size-lg);
}

/* Copy All Button */
.ftnc-copy-all-button {
	width: 100%;
	margin-top: var(--ftnc-space-lg);
}

/* Error Message */
.ftnc-error-message {
	display: flex;
	align-items: flex-start;
	gap: var(--ftnc-space-md);
	padding: var(--ftnc-space-lg);
	background-color: var(--ftnc-color-error-light);
	border: 1px solid var(--ftnc-color-error);
	border-radius: var(--ftnc-radius-md);
	color: var(--ftnc-color-error);
	font-size: var(--ftnc-font-size-sm);
	margin-top: var(--ftnc-space-lg);
	animation: slideDown var(--ftnc-transition-normal) ease-out;
}

.ftnc-error-message.hidden {
	display: none;
}

.ftnc-icon {
	width: 20px;
	height: 20px;
	flex-shrink: 0;
	margin-top: 2px;
}

/* ============================================================================
   REFERENCE SECTION
   ============================================================================ */

.ftnc-reference-section {
	margin-top: var(--ftnc-space-2xl);
}

.ftnc-section-title {
	font-size: var(--ftnc-font-size-lg);
	font-weight: var(--ftnc-font-weight-bold);
	color: var(--ftnc-color-text-primary);
	margin: 0 0 var(--ftnc-space-lg) 0;
}

.ftnc-table-wrapper {
	overflow-x: auto;
	border-radius: var(--ftnc-radius-md);
	border: 1px solid var(--ftnc-color-border);
	box-shadow: var(--ftnc-shadow-sm);
}

.ftnc-reference-table {
	width: 100%;
	border-collapse: collapse;
	background-color: var(--ftnc-color-background);
	font-size: var(--ftnc-font-size-sm);
}

.ftnc-reference-table thead {
	background-color: var(--ftnc-color-background-alt);
	border-bottom: 2px solid var(--ftnc-color-border);
}

.ftnc-reference-table th {
	padding: 12px 16px;
	text-align: left;
	font-weight: var(--ftnc-font-weight-semibold);
	color: var(--ftnc-color-text-primary);
	text-transform: uppercase;
	letter-spacing: 0.5px;
	font-size: var(--ftnc-font-size-xs);
	border-bottom: 1px solid var(--ftnc-color-border);
}

.ftnc-reference-table td {
	padding: 12px 16px;
	border-bottom: 1px solid var(--ftnc-color-border-light);
	color: var(--ftnc-color-text-primary);
}

.ftnc-reference-table tbody tr:hover {
	background-color: var(--ftnc-color-background-alt);
}

.ftnc-reference-table tbody tr:last-child td {
	border-bottom: none;
}

.ftnc-numeric {
	text-align: right;
	font-variant-numeric: tabular-nums;
	font-family: 'Courier New', monospace;
	color: var(--ftnc-color-text-secondary);
}

/* ============================================================================
   ANIMATIONS
   ============================================================================ */

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

@keyframes fadeIn {
	from {
		opacity: 0;
	}
	to {
		opacity: 1;
	}
}

.ftnc-fade-in {
	animation: fadeIn var(--ftnc-transition-normal) ease-out;
}

/* ============================================================================
   ACCESSIBILITY
   ============================================================================ */

/* High contrast mode support */
@media (prefers-contrast: more) {
	.ftnc-input,
	.ftnc-select {
		border-width: 2px;
	}

	.ftnc-button {
		border: 2px solid transparent;
	}

	.ftnc-button-primary {
		border-color: var(--ftnc-color-primary-hover);
	}
}

/* Reduced motion support */
@media (prefers-reduced-motion: reduce) {
	.ftnc-input,
	.ftnc-select,
	.ftnc-button,
	.ftnc-copy-button {
		transition: none;
	}

	.ftnc-error-message {
		animation: none;
	}
}

/* Focus visible for keyboard navigation */
.ftnc-input:focus-visible,
.ftnc-select:focus-visible,
.ftnc-button:focus-visible {
	outline: 2px solid var(--ftnc-color-primary);
	outline-offset: 2px;
}

/* ============================================================================
   PRINT STYLES
   ============================================================================ */

@media print {
	.ftnc-button-group,
	.ftnc-convert-button,
	.ftnc-reset-button,
	.ftnc-copy-button,
	.ftnc-copy-all-button {
		display: none;
	}

	.ftnc-converter-section,
	.ftnc-results-card {
		box-shadow: none;
		border: 1px solid #ccc;
	}
}