:root {
	color-scheme: light dark;
	--bg: #ffffff;
	--fg: #0b0d12;
	--muted: #5b6472;
	--accent: #2f6df6;
	--border: #e4e7ec;
	--danger: #b42318;
	--radius: 10px;
	--space: 1rem;
	--font: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}

@media (prefers-color-scheme: dark) {
	:root {
		--bg: #0b0d12;
		--fg: #f4f6fa;
		--muted: #9aa4b2;
		--accent: #6f9bff;
		--border: #232833;
		--danger: #ff9a8f;
	}
}

* {
	box-sizing: border-box;
}

body {
	margin: 0;
	background: var(--bg);
	color: var(--fg);
	font-family: var(--font);
	line-height: 1.55;
	-webkit-font-smoothing: antialiased;
}

.shell {
	max-width: 42rem;
	margin: 0 auto;
	padding: calc(var(--space) * 3) var(--space);
}

h1 {
	margin: 0 0 0.5rem;
	font-size: clamp(1.6rem, 4vw, 2.25rem);
	letter-spacing: -0.02em;
}

.lede {
	margin: 0 0 0.75rem;
	font-size: 1.05rem;
}

.hint {
	margin: 0;
	color: var(--muted);
}

.btn {
	display: inline-flex;
	align-items: center;
	gap: 0.5rem;
	padding: 0.55rem 0.9rem;
	border: 1px solid transparent;
	border-radius: var(--radius);
	background: var(--accent);
	color: #fff;
	font: inherit;
	font-weight: 500;
	cursor: pointer;
}

.btn:hover {
	filter: brightness(1.05);
}

.btn-secondary {
	background: transparent;
	color: var(--fg);
	border-color: var(--border);
}

.card {
	padding: var(--space);
	border: 1px solid var(--border);
	border-radius: var(--radius);
	background: var(--bg);
}

.input,
.select,
.textarea {
	width: 100%;
	padding: 0.55rem 0.7rem;
	border: 1px solid var(--border);
	border-radius: var(--radius);
	background: var(--bg);
	color: var(--fg);
	font: inherit;
}

.field {
	display: grid;
	grid-template-columns: minmax(0, 1fr);
	gap: 0.35rem;
	margin-bottom: var(--space);
}

.field > label {
	font-size: 0.875rem;
	color: var(--muted);
}

/*
 * 390px-safe, like .grid below. A grid with no column list gets one implicit
 * auto column, and an auto column is never narrower than its widest item's
 * min-content width. One nowrap scrolling strip (days, time slots) anywhere
 * inside an item therefore widened the whole column past the screen: the page
 * scrolled sideways instead of the strip scrolling on its own. minmax(0, 1fr)
 * caps the column at the container; the min-width rule keeps a child from
 * bringing the same floor back if an app redefines the columns. :where() adds
 * no specificity, so a min-width the app sets on a child still wins.
 */
.stack {
	display: grid;
	grid-template-columns: minmax(0, 1fr);
	gap: var(--space);
}

:where(.field, .stack, .list) > * {
	min-width: 0;
}

.row {
	display: flex;
	align-items: center;
	gap: 0.75rem;
	flex-wrap: wrap;
}

/*
 * 390px-safe. An unclamped minmax track overflows a 390px viewport once the
 * shell padding is subtracted, and nothing in the pipeline ever looked at a
 * phone-width layout, so every generated app inherited the horizontal scroll.
 * min() clamps the track to the container instead.
 */
.grid {
	display: grid;
	gap: var(--space);
	grid-template-columns: repeat(auto-fit, minmax(min(15rem, 100%), 1fr));
}

.list {
	display: grid;
	grid-template-columns: minmax(0, 1fr);
	gap: 0.5rem;
	margin: 0;
	padding: 0;
	list-style: none;
}

.list-item {
	display: flex;
	align-items: center;
	justify-content: space-between;
	gap: 0.75rem;
	flex-wrap: wrap;
	padding: 0.7rem 0.85rem;
	border: 1px solid var(--border);
	border-radius: var(--radius);
}

.table {
	width: 100%;
	border-collapse: collapse;
}

.table th,
.table td {
	padding: 0.6rem 0.5rem;
	text-align: left;
	border-bottom: 1px solid var(--border);
}

.table th {
	font-size: 0.8125rem;
	color: var(--muted);
	font-weight: 600;
}

.empty {
	padding: calc(var(--space) * 2);
	text-align: center;
	color: var(--muted);
}

.empty-title {
	margin: 0 0 0.25rem;
	color: var(--fg);
	font-weight: 600;
}

/* Loading. Every fetch has one; without a primitive each app invented its own. */
.loading {
	display: flex;
	align-items: center;
	justify-content: center;
	gap: 0.6rem;
	padding: calc(var(--space) * 1.5);
	color: var(--muted);
}

.spinner {
	flex: none;
	width: 1.15rem;
	height: 1.15rem;
	border: 2px solid var(--border);
	border-top-color: var(--accent);
	border-radius: 50%;
	animation: fab-spin 0.7s linear infinite;
}

@keyframes fab-spin {
	to {
		transform: rotate(360deg);
	}
}

/* Placeholder for content whose shape is known before its data arrives. */
.skeleton {
	display: block;
	height: 1rem;
	border-radius: calc(var(--radius) / 2);
	background: linear-gradient(90deg, var(--border), transparent, var(--border));
	background-size: 200% 100%;
	animation: fab-shimmer 1.2s linear infinite;
}

@keyframes fab-shimmer {
	to {
		background-position: -200% 0;
	}
}

/* Error strip: a failure the user can see and retry, never a silent no-op. */
.alert {
	display: flex;
	align-items: center;
	justify-content: space-between;
	gap: 0.75rem;
	flex-wrap: wrap;
	padding: 0.7rem 0.85rem;
	border: 1px solid var(--border);
	border-left: 3px solid var(--muted);
	border-radius: var(--radius);
}

.alert-error {
	border-left-color: var(--danger);
	color: var(--danger);
}

.badge {
	display: inline-block;
	padding: 0.1rem 0.5rem;
	border: 1px solid var(--border);
	border-radius: 999px;
	font-size: 0.8125rem;
	color: var(--muted);
}

/*
 * The scaffold had exactly one @media rule (prefers-color-scheme) and no width
 * breakpoint at all, so the shell was a 42rem column at every size.
 * Mobile-first stays the default; these only widen it.
 */
@media (min-width: 48rem) {
	.shell {
		max-width: 52rem;
		padding: calc(var(--space) * 3) calc(var(--space) * 1.5);
	}
}

@media (min-width: 64rem) {
	.shell {
		max-width: 64rem;
	}
}

@media (prefers-reduced-motion: reduce) {
	.spinner,
	.skeleton {
		animation: none;
	}
}

:where(a, button, input, select, textarea):focus-visible {
	outline: 3px solid var(--accent);
	outline-offset: 2px;
}

/* ---- Suma-Resta 3C ---- */
:root, html { color-scheme: light; --bg: #fffaf0; --fg: #2b2240; --muted: #6b6280; --accent: #6a4cff; --border: #eadff7; }
body { background: #fffaf0 radial-gradient(circle at 10% 10%, #ffe3f1 0, transparent 30%), radial-gradient(circle at 90% 20%, #dff3ff 0, transparent 30%); font-family: "Trebuchet MS", "Comic Sans MS", system-ui, sans-serif; color: #2b2240; }
.app.big-text { font-size: 1.25rem; }
.top { display: flex; justify-content: space-between; align-items: center; gap: .5rem; flex-wrap: wrap; padding: .75rem 1rem; }
.logo { background: none; border: 0; font: inherit; font-size: 1.3rem; font-weight: 800; color: #2b2240; cursor: pointer; }
.logo b { color: #ff4f8b; }
.small { padding: .4rem .7rem; font-size: .9rem; }
.progress-wrap { display: flex; align-items: center; gap: .6rem; padding: 0 1rem; max-width: 64rem; margin: 0 auto; }
.progress { flex: 1; height: 1.1rem; background: #eee6fb; border-radius: 99px; overflow: hidden; border: 2px solid #d9cbf5; }
.bar { height: 100%; background: linear-gradient(90deg, #ff4f8b, #ffb627, #2ec4b6); transition: width .5s; }
.pct { font-weight: 800; white-space: nowrap; }
.shell { padding-top: 1.5rem; }
.hero { text-align: center; margin-bottom: 1.5rem; }
.hero h1 { font-size: clamp(2.2rem, 7vw, 3.5rem); color: #6a4cff; text-shadow: 3px 3px 0 #ffd23f; }
.lede { font-weight: 700; font-size: 1.3rem; }
.stage-grid { display: grid; gap: 1rem; grid-template-columns: repeat(auto-fit, minmax(min(16rem, 100%), 1fr)); }
.stage-card { display: flex; flex-direction: column; align-items: center; gap: .35rem; padding: 1.5rem 1rem; border: 0; border-radius: 28px; font: inherit; color: #2b2240; cursor: pointer; box-shadow: 0 8px 0 rgba(0,0,0,.12); transition: transform .15s; }
.stage-card:hover { transform: translateY(-4px) rotate(-1deg); }
.pink { --c: #ff4f8b; --cl: #ffe0ec; } .blue { --c: #3a86ff; --cl: #dcebff; } .green { --c: #16a37a; --cl: #d6f5e9; }
.stage-card { background: var(--cl); border: 4px solid var(--c); }
.stage-emoji { font-size: 3rem; }
.stage-n { font-weight: 700; color: var(--c); }
.stage-title { font-size: 1.7rem; font-weight: 900; color: var(--c); }
.stage-count { font-weight: 800; }
.chip { display: inline-block; padding: .2rem .7rem; border-radius: 99px; background: #fff; border: 2px solid #e2d6f7; font-size: .85rem; font-weight: 700; }
.stage { background: var(--cl); border: 4px solid var(--c); border-radius: 28px; padding: 1.25rem; display: grid; gap: 1rem; }
.stage h2 { margin: 0; color: var(--c); font-size: 1.6rem; scroll-margin-top: 1rem; }
.back { justify-self: start; background: #fff; border: 2px solid var(--c); color: var(--c); border-radius: 99px; padding: .35rem .9rem; font: inherit; font-weight: 700; cursor: pointer; }
.activity { background: #fff; border-radius: 22px; padding: 1.1rem; display: grid; gap: 1rem; min-width: 0; }
.act-head { display: flex; justify-content: space-between; align-items: center; }
.read-btn { font-size: 1.4rem; width: 3rem; height: 3rem; border-radius: 50%; border: 3px solid #ffd23f; background: #fff8d6; cursor: pointer; }
.story { background: #fff8e6; border: 3px dashed #ffb627; border-radius: 18px; padding: 1rem; display: flex; gap: .8rem; align-items: center; flex-wrap: wrap; justify-content: center; text-align: center; }
.story p { margin: 0; font-size: 1.1rem; flex: 1 1 14rem; }
.story-emoji { font-size: 2.6rem; }
.big-num { font-size: 3rem; font-weight: 900; color: #6a4cff; letter-spacing: .1em; }
.prompt { margin: 0; font-weight: 700; font-size: 1.1rem; }
.center { justify-content: center; }
.cards { display: flex; gap: .8rem; justify-content: center; min-height: 4.5rem; flex-wrap: wrap; }
.num-card { width: 4.2rem; height: 4.2rem; font-size: 2rem; font-weight: 900; border-radius: 16px; border: 3px solid #6a4cff; background: #efeaff; color: #2b2240; cursor: grab; box-shadow: 0 5px 0 #6a4cff; }
.num-card.picked { transform: translateY(-6px); background: #ffd23f; }
.slots { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: .5rem; }
.slot { display: flex; flex-direction: column; align-items: center; gap: .3rem; padding: .7rem .3rem; min-height: 9rem; border-radius: 18px; border: 3px dashed; font: inherit; cursor: pointer; color: #2b2240; }
.s0 { border-color: #ff4f8b; background: #ffeef4; } .s1 { border-color: #3a86ff; background: #eaf3ff; } .s2 { border-color: #16a37a; background: #e6faf2; }
.slot.filled { border-style: solid; }
.slot-label { font-size: .8rem; font-weight: 800; }
.slot-val { font-size: 2rem; font-weight: 900; }
.blocks { display: flex; flex-wrap: wrap; gap: 3px; justify-content: center; }
.b { display: block; } .b0 { width: 16px; height: 16px; background: #ff4f8b; } .b1 { width: 5px; height: 22px; background: #3a86ff; } .b2 { width: 7px; height: 7px; background: #16a37a; }
.opt, .op-btn { font: inherit; font-size: 1.4rem; font-weight: 900; padding: .7rem 1.4rem; border-radius: 16px; border: 3px solid #6a4cff; background: #fff; cursor: pointer; box-shadow: 0 4px 0 #6a4cff; color: #2b2240; }
.op-btn.plus { border-color: #16a37a; box-shadow: 0 4px 0 #16a37a; } .op-btn.minus { border-color: #ff4f8b; box-shadow: 0 4px 0 #ff4f8b; }
.fb { padding: .8rem 1rem; border-radius: 16px; font-weight: 700; }
.fb-ok { background: #d6f5e9; border: 2px solid #16a37a; } .fb-try { background: #fff1d6; border: 2px solid #ffb627; } .fb-info { background: #ece6ff; border: 2px solid #6a4cff; }
.btn { border-radius: 99px; font-weight: 800; padding: .65rem 1.2rem; justify-self: start; }
.big { font-size: 1.1rem; }
.columns { display: grid; grid-template-columns: repeat(3, 4rem); gap: .4rem; justify-content: center; font-size: 2rem; font-weight: 900; }
.col-head { text-align: center; font-size: 1rem; border-radius: 10px; color: #fff; }
.col-head.c { background: #ff4f8b; } .col-head.d { background: #3a86ff; } .col-head.u { background: #16a37a; }
.cell { position: relative; text-align: center; }
.op { position: absolute; left: -1.6rem; }
.line { grid-column: 1 / -1; height: 4px; background: #2b2240; border-radius: 4px; }
.cell-input, .num-input { font: inherit; font-weight: 900; text-align: center; border: 3px solid #c9b8f5; border-radius: 12px; background: #faf8ff; color: #2b2240; }
.cell-input { width: 100%; font-size: 2rem; }
.cell-input.bad { border-color: #ff4f4f; background: #ffecec; }
.num-input { width: 7rem; font-size: 1.6rem; }
.steps { display: flex; gap: .4rem; padding: 0; margin: 0; list-style: none; flex-wrap: wrap; justify-content: center; }
.steps li { padding: .25rem .7rem; border-radius: 99px; background: #eee; font-weight: 700; font-size: .9rem; }
.steps li.now { background: #ffd23f; } .steps li.done { background: #16a37a; color: #fff; }
.why-card { text-align: left; font: inherit; font-size: 1.05rem; padding: .9rem 1rem; border-radius: 16px; border: 3px solid #3a86ff; background: #eaf3ff; cursor: pointer; color: #2b2240; }
@media (max-width: 30rem) { .columns { grid-template-columns: repeat(3, 3.3rem); } .num-card { width: 3.6rem; height: 3.6rem; } }