/* ================================================================
   teaching.css  —  Shared stylesheet for SimJS teaching examples
   ================================================================ */

@import url('https://fonts.googleapis.com/css2?family=Inter:ital,wght@0,400;0,500;0,600;0,700;0,800;1,400&display=swap');

/* ── Reset ────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; }

/* ── Page & background ────────────────────────────────────────── */
html, body {
	font-family: 'Inter', 'Segoe UI', Helvetica, Arial, sans-serif;
	background-color: #eef2ff;
	background-image:
		radial-gradient(ellipse 70% 40% at 10%  5%,  rgba(219,234,254,0.95) 0%, transparent 55%),
		radial-gradient(ellipse 55% 45% at 90% 95%, rgba(233, 240, 254, 0.95) 0%, transparent 55%);
	min-width: 1024px;
	min-height: 100vh;
	width: 100%; 
	color: #1e293b;
	padding-bottom: 52px;
	line-height: 1.65;
	margin: 0;
  	padding: 0;
}

/* ── Page header banner ───────────────────────────────────────── */
.page-header {
	background: linear-gradient(120deg, #2e4681 0%, #466ee5 48%, #0891b2 100%);
	padding: 26px 32px 22px;
	text-align: center;
	box-shadow: 0 4px 28px rgba(49,46,129,0.38);
	margin-bottom: 32px;
	position: relative;
	overflow: hidden;
}

/* Decorative background circles */
.page-header::before,
.page-header::after {
	content: '';
	position: absolute;
	border-radius: 50%;
	opacity: 0.10;
	background: #fff;
	pointer-events: none;
}
.page-header::before { width: 380px; height: 380px; top: -190px; left: -80px; }
.page-header::after  { width: 220px; height: 220px; bottom: -110px; right:  50px; }

.page-header h1 {
	font-size: 1.95rem;
	font-weight: 100;
	color: #fff;
	letter-spacing: -0.4px;
	text-shadow: 0 2px 14px rgba(0,0,0,0.40);
	position: relative;   /* sits above ::before / ::after */
	margin: 0;
}

/* Fallback: plain h1 when .page-header wrapper is not used */
body > h1,
main > h1 {
	text-align: center;
	font-size: 1.9rem;
	font-weight: 800;
	background: linear-gradient(90deg, #2e3f81, #4676e5 50%, #0891b2);
	-webkit-background-clip: text;
	-webkit-text-fill-color: transparent;
	background-clip: text;
	margin: 30px 0 24px;
}

/* ── Layout wrapper ───────────────────────────────────────────── */
main,
.content-wrapper {
	max-width: 1240px;
	margin: 0 auto;
	padding: 0 22px;
}

/* ── Card ─────────────────────────────────────────────────────── */
.card {
	background: #fff;
	border-radius: 20px;
	box-shadow: 0 4px 28px rgba(70, 107, 229, 0.09), 0 1px 4px rgba(0,0,0,0.05);
	padding: 24px 28px;
	margin-bottom: 24px;
	border: 1px solid rgba(199, 221, 254, 0.55);
}

/* ── Simulation panel (canvas + controls side by side) ────────── */
.sim-panel {
	display: flex;
	min-width: 500px;
	gap: 24px;
	align-items: flex-start;
	flex-wrap: wrap;
}

.sim-canvas-wrap { flex: 1 1 auto; min-width: 500px; }

/* Let the canvas fill its flex wrapper so it shrinks alongside the controls panel */
.sim-canvas-wrap canvas { width: 100%; }

canvas {
	border: 3px solid #a5cffc;
	border-radius: 16px;
	display: block;
	max-width: 100%;
	box-shadow: 0 8px 36px rgba(79,70,229,0.22), 0 2px 6px rgba(0,0,0,0.08);
}

.canvas-hint {
	font-size: 0.82rem !important;
	color: #6b7280 !important;
	margin: 8px 0 0 2px !important;
}

/* ── Controls panel ───────────────────────────────────────────── */
.controls-panel {
	flex: 0 0 230px;
	min-width: 195px;
	background: #f5f7ff;
	border-radius: 16px;
	padding: 18px 20px 22px;
	border: 1px solid #dde3f8;
	box-shadow: inset 0 1px 0 rgba(255,255,255,0.8);
	margin-bottom: 24px;
}

.controls-panel > h3 {
	margin: 0 0 16px !important;
	font-size: 0.78rem !important;
	color: #6397f1 !important;
	font-weight: 700 !important;
	text-transform: uppercase;
	letter-spacing: 0.8px;
	border-bottom: 1px solid #e0e7ff;
	padding-bottom: 8px;
}

.controls-grid {
	display: grid;
	grid-template-columns: auto 1fr;
	gap: 10px 12px;
	align-items: center;
}

.controls-grid .full-width { grid-column: 1 / -1; }

.plots-grid {
	display: grid;	
	grid-template-columns: auto auto;
	gap: 2px 2px;
	align-items: center;
}


/* ── Labels ───────────────────────────────────────────────────── */
label {
	font-size: 0.84rem;
	font-weight: 500;
	color: #4b5563;
	white-space: nowrap;
	cursor: default;
}

/* ── Stat value display ───────────────────────────────────────── */
.stat-value {
	font-variant-numeric: tabular-nums;
	font-size: 0.9rem;
	font-weight: 600;
	color: #467be5;
	background: #eff0ff;
	padding: 4px 10px;
	border-radius: 8px;
	border: 1px solid #c7d2fe;
	display: block;
	text-align: right;
}

/* ── Inputs ───────────────────────────────────────────────────── */
input[type="number"],
input[type="text"],
select {
	width: 100%;
	padding: 6px 10px;
	border: 2px solid #c7d2fe;
	border-radius: 8px;
	font-size: 0.88rem;
	font-family: inherit;
	color: #1e293b;
	background: #fff;
	outline: none;
	transition: border-color 0.18s, box-shadow 0.18s;
}

input[type="number"]:focus,
input[type="text"]:focus,
select:focus {
	border-color: #4673e5;
	box-shadow: 0 0 0 3px rgba(79,70,229,0.13);
}

input[type="range"] {
	width: 100%;
	accent-color: #4673e5;
	cursor: pointer;
	vertical-align: middle;
}

input[type="checkbox"] {
	width: 17px;
	height: 17px;
	accent-color: #4673e5;
	cursor: pointer;
}

/* ── Buttons ──────────────────────────────────────────────────── */
button {
	display: inline-flex;
	align-items: center;
	justify-content: center;
	gap: 6px;
	width: 100%;
	padding: 9px 18px;
	border: none;
	border-radius: 10px;
	font-size: 0.88rem;
	font-family: inherit;
	font-weight: 600;
	cursor: pointer;
	transition: transform 0.10s, box-shadow 0.14s, background 0.14s;
	background: linear-gradient(135deg, #4673e5 0%, #6389f1 100%);
	color: #fff;
	box-shadow: 0 3px 12px rgba(70, 102, 229, 0.32);
	margin-top: 2px;
}

button:hover {
	transform: translateY(-2px);
	box-shadow: 0 6px 18px rgba(79,70,229,0.40);
	background: linear-gradient(135deg, #3869ca 0%, #4673e5 100%);
}

button:active {
	transform: translateY(0);
	box-shadow: 0 2px 6px rgba(70, 112, 229, 0.25);
}

/* Secondary button variant (e.g. Pause) */
button.btn-secondary {
	background: linear-gradient(135deg, #0891b2 0%, #06b6d4 100%);
	box-shadow: 0 3px 12px rgba(8,145,178,0.32);
}

button.btn-secondary:hover {
	background: linear-gradient(135deg, #0e7490 0%, #0891b2 100%);
	box-shadow: 0 6px 18px rgba(8,145,178,0.40);
}

/* Inline (non-full-width) button variant */
button.btn-inline {
	width: auto;
	padding: 3px 12px;
}

/* ── Section headings ─────────────────────────────────────────── */
h2 {
	font-size: 1.22rem;
	font-weight: 700;
	color: #2e4081;
	margin: 24px 0 10px;
	padding-bottom: 8px;
	border-bottom: 2px solid #e0e7ff;
}

h3 {
	font-size: 1.00rem;
	font-weight: 600;
	color: #3869ca;
	margin: 16px 0 6px;
}

h4 {
	font-size: 0.95rem;
	font-weight: 500;
	color: #448dc9;
	margin: 16px 0 6px;
}

p {
	font-size: 0.95rem;
	color: #374151;
	margin-bottom: 10px;
}

/* ── Theory / text card accent ────────────────────────────────── */
.theory {
	border-left: 4px solid #4673e5;
}

.theory h2:first-child { margin-top: 0; }

/* ── Optional info badges ─────────────────────────────────────── */
.badge {
	display: inline-block;
	padding: 3px 11px;
	border-radius: 20px;
	font-size: 0.74rem;
	font-weight: 600;
	letter-spacing: 0.4px;
	text-transform: uppercase;
}
.badge-pde    { background: #dbeafe; color: #1e40af; }
.badge-ode    { background: #dcfce7; color: #166534; }
.badge-linalg { background: #fef3c7; color: #92400e; }
.badge-opt    { background: #fce7f3; color: #9d174d; }

/* ── Responsive ───────────────────────────────────────────────── */
@media (max-width: 820px) {
	.sim-panel      { flex-direction: column; }
	.controls-panel { flex: 1 1 auto; min-width: unset; }
	.page-header h1,
	body > h1       { font-size: 1.4rem; }
	.card           { padding: 18px 16px; }
}