:root {
	--bg: #f2f5fa;
	--surface: #ffffff;
	--surface-soft: #f8fbff;
	--text: #12243c;
	--muted: #5e7190;
	--border: #d6dfec;
	--primary: #1e63f1;
	--primary-hover: #1550ca;
	--ok: #0f8f5f;
	--warn: #9b5b00;
	--error: #bd2430;
	--shadow: 0 10px 24px rgba(16, 35, 68, 0.08);
}

* { box-sizing: border-box; }

html, body {
	margin: 0;
	padding: 0;
}

body {
	font-family: Inter, Segoe UI, Roboto, Arial, sans-serif;
	color: var(--text);
	background: linear-gradient(180deg, #e9f0fb 0%, var(--bg) 38%, var(--bg) 100%);
	line-height: 1.45;
}

.skip-link {
	position: absolute;
	left: 12px;
	top: -100px;
	z-index: 200;
	background: #111827;
	color: #fff;
	padding: 8px 10px;
	border-radius: 8px;
	text-decoration: none;
}

.skip-link:focus {
	top: 10px;
}

.main-header,
.container,
.site-footer {
	width: min(1200px, 96vw);
	margin-left: auto;
	margin-right: auto;
}

.main-header {
	margin-top: 16px;
	margin-bottom: 10px;
	padding: 18px 20px;
	background: var(--surface);
	border: 1px solid var(--border);
	border-radius: 14px;
	box-shadow: var(--shadow);
}

.main-header h1 {
	margin: 0;
	font-size: clamp(1.34rem, 2.5vw, 2rem);
}

.subtitle {
	margin: 6px 0 0;
	font-size: 0.95rem;
	color: var(--muted);
}

.container {
	display: grid;
	gap: 12px;
	margin-bottom: 18px;
}

.card {
	background: var(--surface);
	border: 1px solid var(--border);
	border-radius: 14px;
	padding: 14px;
	box-shadow: var(--shadow);
}

.card h2 {
	margin: 0;
	font-size: 1.15rem;
}

.helper {
	margin: 8px 0 12px;
	font-size: 0.9rem;
	color: var(--muted);
}

.quick-example {
	margin: 10px 0 0;
	font-size: 0.88rem;
	color: var(--muted);
	padding: 8px 10px;
	border-radius: 10px;
	border: 1px dashed var(--border);
	background: color-mix(in srgb, var(--surface-soft) 86%, var(--primary) 14%);
}

.app-message,
.app-warning {
	border-radius: 10px;
	padding: 10px 12px;
	margin-bottom: 10px;
	font-size: 0.9rem;
}

.app-message {
	border: 1px solid color-mix(in srgb, var(--error) 42%, var(--border) 58%);
	background: color-mix(in srgb, #ffe8ea 72%, #fff 28%);
	color: var(--error);
}

.app-warning {
	border: 1px solid color-mix(in srgb, var(--warn) 38%, var(--border) 62%);
	background: color-mix(in srgb, #fff1df 78%, #fff 22%);
	color: var(--warn);
}

.form-grid {
	display: grid;
	grid-template-columns: 1fr 1fr;
	gap: 10px;
}

.field-group {
	display: grid;
	gap: 6px;
}

.field-group label,
.slider-wrap label,
legend {
	font-weight: 700;
	font-size: 0.92rem;
}

textarea,
input[type="range"],
button {
	font: inherit;
}

input[type="text"] {
	width: 100%;
	min-height: 38px;
	padding: 0 10px;
	border: 1px solid var(--border);
	border-radius: 9px;
	background: var(--surface-soft);
	color: var(--text);
}

textarea {
	width: 100%;
	padding: 10px;
	border: 1px solid var(--border);
	border-radius: 10px;
	background: var(--surface-soft);
	color: var(--text);
	resize: vertical;
	min-height: 150px;
}

small,
.fieldset-help {
	color: var(--muted);
	font-size: 0.82rem;
	margin: 0;
}

.models-fieldset {
	margin: 12px 0 0;
	padding: 10px;
	border: 1px solid var(--border);
	border-radius: 12px;
	background: var(--surface-soft);
}

.models-grid {
	margin-top: 8px;
	display: grid;
	grid-template-columns: repeat(4, minmax(140px, 1fr));
	gap: 8px;
}

.check-item {
	display: flex;
	gap: 8px;
	align-items: center;
	padding: 8px;
	border: 1px solid var(--border);
	border-radius: 9px;
	background: #fff;
	font-size: 0.9rem;
}

.check-item input {
	accent-color: var(--primary);
	width: 16px;
	height: 16px;
}

.controls-row {
	margin-top: 12px;
	display: flex;
	flex-wrap: wrap;
	justify-content: space-between;
	gap: 12px;
	align-items: flex-end;
}

.slider-wrap {
	display: grid;
	gap: 6px;
	min-width: 220px;
}

.buttons-row {
	display: flex;
	gap: 8px;
	flex-wrap: wrap;
}

.button {
	border-radius: 10px;
	border: 1px solid var(--border);
	min-height: 40px;
	padding: 0 14px;
	font-weight: 700;
	cursor: pointer;
	transition: background-color .16s ease, border-color .16s ease, transform .1s ease;
}

.button:active { transform: translateY(1px); }

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

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

.button-secondary,
.button-tertiary {
	background: var(--surface-soft);
	color: var(--text);
}

.button-secondary:hover,
.button-tertiary:hover {
	background: color-mix(in srgb, var(--surface-soft) 74%, var(--primary) 26%);
}

.button:focus-visible,
textarea:focus-visible,
input:focus-visible,
a:focus-visible {
	outline: 2px solid color-mix(in srgb, var(--primary) 60%, #fff 40%);
	outline-offset: 2px;
}

.empty-state p {
	margin: 8px 0 0;
	color: var(--muted);
}

.results {
	display: grid;
	gap: 12px;
}

.section-head {
	display: flex;
	justify-content: space-between;
	align-items: center;
	gap: 10px;
	flex-wrap: wrap;
}

.export-buttons {
	display: flex;
	gap: 8px;
	flex-wrap: wrap;
}

.results-grid {
	margin-top: 10px;
	display: grid;
	grid-template-columns: repeat(2, minmax(260px, 1fr));
	gap: 10px;
}

.result-item {
	border: 1px solid var(--border);
	border-radius: 12px;
	padding: 11px;
	background: var(--surface-soft);
	display: grid;
	gap: 8px;
}

.result-item h3 {
	margin: 0;
	font-size: 1rem;
}

.equation {
	font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
	font-size: 0.91rem;
	padding: 8px;
	border: 1px dashed var(--border);
	border-radius: 9px;
	background: #fff;
	overflow-wrap: anywhere;
}

.equation-plain {
	font-size: 0.82rem;
	color: var(--muted);
	font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

.metrics-list {
	display: grid;
	grid-template-columns: repeat(2, minmax(100px, 1fr));
	gap: 7px;
	font-size: 0.87rem;
}

.metric {
	padding: 7px;
	border-radius: 8px;
	border: 1px solid var(--border);
	background: #fff;
}

.metric span {
	display: block;
	color: var(--muted);
	font-size: 0.78rem;
}

.copy-row {
	display: flex;
	gap: 7px;
	flex-wrap: wrap;
}

.tag-na {
	font-size: 0.83rem;
	color: var(--warn);
	font-weight: 700;
}

.chart-summary {
	margin: 8px 0 12px;
	color: var(--muted);
	font-size: 0.9rem;
}

.chart-toolbar {
	display: grid;
	gap: 10px;
	margin-top: 8px;
	padding: 10px;
	border: 1px solid var(--border);
	border-radius: 12px;
	background: var(--surface-soft);
}

.chart-meta-grid {
	display: grid;
	grid-template-columns: 2fr 1fr 1fr;
	gap: 8px;
}

.field-group.compact {
	gap: 4px;
}

.field-group.compact label {
	font-size: 0.82rem;
	font-weight: 700;
	color: var(--muted);
}

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

.menu-dropdown {
	position: relative;
}

.menu-dropdown > summary {
	list-style: none;
	display: inline-flex;
	align-items: center;
	justify-content: center;
	min-width: 170px;
}

.menu-dropdown > summary::-webkit-details-marker {
	display: none;
}

.menu-dropdown[open] > summary {
	border-color: color-mix(in srgb, var(--primary) 54%, var(--border) 46%);
	background: color-mix(in srgb, var(--surface-soft) 64%, var(--primary) 36%);
}

.menu-panel {
	position: absolute;
	z-index: 8;
	top: calc(100% + 6px);
	left: 0;
	min-width: 260px;
	padding: 9px;
	border: 1px solid var(--border);
	border-radius: 12px;
	background: var(--surface);
	box-shadow: var(--shadow);
}

.download-list {
	display: grid;
	gap: 6px;
	min-width: 180px;
}

.menu-item {
	min-height: 34px;
	padding: 0 10px;
	border-radius: 8px;
	border: 1px solid var(--border);
	background: var(--surface-soft);
	color: var(--text);
	cursor: pointer;
	font-weight: 700;
	text-align: left;
}

.menu-item:hover {
	background: color-mix(in srgb, var(--surface-soft) 70%, var(--primary) 30%);
}

.chart-toggles {
	display: grid;
	gap: 6px;
	max-height: 220px;
	overflow: auto;
}

.chart-toggle {
	display: flex;
	align-items: center;
	justify-content: space-between;
	gap: 7px;
	padding: 7px 9px;
	border: 1px solid var(--border);
	border-radius: 10px;
	background: color-mix(in srgb, var(--surface-soft) 86%, var(--surface) 14%);
	font-size: 0.83rem;
}

.chart-toggle .left {
	display: inline-flex;
	align-items: center;
	gap: 7px;
}

.chart-swatch {
	width: 10px;
	height: 10px;
	border-radius: 99px;
	flex: 0 0 auto;
}

.chart-toggle input {
	accent-color: var(--primary);
	width: 15px;
	height: 15px;
}

.chart-wrap {
	--plot-left: 72px;
	--plot-top: 56px;
	--plot-width: 600px;
	--plot-height: 320px;
	--plot-bottom: 56px;
	--plot-right: 20px;
	position: relative;
	border: 1px solid var(--border);
	border-radius: 12px;
	padding: 8px;
	background: #fff;
	overflow: hidden;
}

.chart-edit-layer {
	position: absolute;
	inset: 8px;
	pointer-events: none;
	z-index: 2;
}

.chart-label {
	position: absolute;
	pointer-events: auto;
	max-width: min(420px, 70%);
	min-width: 24px;
	padding: 3px 7px;
	border-radius: 8px;
	border: 1px solid transparent;
	font-weight: 700;
	line-height: 1.25;
	text-align: center;
	background: color-mix(in srgb, var(--surface) 74%, transparent 26%);
	color: var(--text);
	white-space: nowrap;
	overflow: hidden;
	text-overflow: ellipsis;
	cursor: text;
	user-select: text;
}

.chart-label[data-empty="1"]::before {
	content: attr(aria-label);
	font-weight: 600;
	opacity: 0.6;
}

.chart-label:focus {
	outline: none;
	border-color: color-mix(in srgb, var(--primary) 54%, var(--border) 46%);
	background: color-mix(in srgb, var(--surface-soft) 72%, var(--surface) 28%);
	box-shadow: 0 0 0 2px color-mix(in srgb, var(--primary) 24%, transparent 76%);
}

.chart-label-title {
	left: calc(var(--plot-left) + (var(--plot-width) / 2));
	top: max(6px, calc(var(--plot-top) - 38px));
	transform: translateX(-50%);
	font-size: 1rem;
}

.chart-label-x {
	left: calc(var(--plot-left) + (var(--plot-width) / 2));
	top: calc(var(--plot-top) + var(--plot-height) + 24px);
	transform: translateX(-50%);
	font-size: 0.86rem;
}

.chart-label-y {
	left: max(6px, calc(var(--plot-left) - 48px));
	top: calc(var(--plot-top) + (var(--plot-height) / 2));
	transform: translate(-50%, -50%) rotate(-90deg);
	transform-origin: center;
	font-size: 0.86rem;
	max-width: 280px;
}

#regressionCanvas {
	width: 100%;
	height: min(56vw, 520px);
	display: block;
}

.chart-tooltip {
	position: absolute;
	pointer-events: none;
	padding: 8px 10px;
	background: rgba(15, 23, 42, 0.96);
	color: #e9eef8;
	border-radius: 8px;
	font-size: 0.79rem;
	max-width: 280px;
	box-shadow: 0 8px 20px rgba(15, 23, 42, 0.28);
	z-index: 3;
}

.legend-list {
	margin: 10px 0 0;
	padding: 0;
	list-style: none;
	display: flex;
	flex-wrap: wrap;
	gap: 8px;
}

.legend-list li {
	display: flex;
	align-items: center;
	gap: 6px;
	font-size: 0.84rem;
	padding: 6px 8px;
	background: color-mix(in srgb, var(--surface-soft) 86%, var(--surface) 14%);
	border: 1px solid var(--border);
	border-radius: 999px;
}

.legend-dot {
	width: 10px;
	height: 10px;
	border-radius: 99px;
	flex: 0 0 auto;
}

.anchor-link {
	color: var(--primary);
	text-decoration: none;
	font-size: 0.87rem;
	font-weight: 600;
}

.anchor-link:hover { text-decoration: underline; }

.table-wrap {
	overflow: auto;
	border: 1px solid var(--border);
	border-radius: 12px;
	max-height: 520px;
	background: #fff;
}

table {
	width: 100%;
	min-width: 780px;
	border-collapse: collapse;
	font-size: 0.86rem;
	font-variant-numeric: tabular-nums;
}

caption {
	padding: 8px;
	text-align: left;
	color: var(--muted);
	font-size: 0.82rem;
}

th,
td {
	padding: 7px 9px;
	border-bottom: 1px solid var(--border);
	text-align: right;
	white-space: nowrap;
}

th {
	position: sticky;
	top: 0;
	z-index: 1;
	background: color-mix(in srgb, var(--surface-soft) 84%, var(--primary) 16%);
}

th:first-child,
td:first-child {
	text-align: center;
}

tbody tr:hover {
	background: color-mix(in srgb, var(--surface-soft) 72%, var(--primary) 28%);
}

@media (max-width: 980px) {
	.form-grid,
	.results-grid,
	.models-grid {
		grid-template-columns: 1fr;
	}

	.chart-meta-grid {
		grid-template-columns: 1fr;
	}

	.menu-dropdown,
	.menu-dropdown > summary {
		width: 100%;
	}

	.menu-panel {
		left: 0;
		right: 0;
		min-width: 0;
	}

	.buttons-row {
		width: 100%;
	}

	.buttons-row .button {
		flex: 1;
	}
}

@media (prefers-color-scheme: dark) {
	:root {
		--bg: #0a1424;
		--surface: #0f1b31;
		--surface-soft: #12223b;
		--text: #e8eefb;
		--muted: #9eb2d3;
		--border: #284064;
		--primary: #66a2ff;
		--primary-hover: #4b8ef2;
		--ok: #3ecf95;
		--warn: #ffb95b;
		--error: #ff8b9a;
		--shadow: 0 12px 28px rgba(0, 0, 0, 0.35);
	}

	body {
		background: radial-gradient(circle at top, #142846 0%, var(--bg) 58%);
	}

	.equation,
	.table-wrap,
	.chart-wrap,
	.check-item,
	.metric {
		background: #0e192d;
	}

	.chart-tooltip {
		background: rgba(2, 10, 23, 0.96);
		color: #e6f0ff;
	}
}