:root {
	color-scheme: light;
	--sumi: #15231d;
	--ink-soft: #53615a;
	--paper: #f6f8f5;
	--surface: #fbfcfa;
	--rule: #cbd4ce;
	--vermilion: #b84232;
	--moss: #315f4d;
	--mist: #dfe9e3;
	--warm: #f3e8df;
}

* { box-sizing: border-box; }

body {
	margin: 0;
	background: var(--paper);
	color: var(--sumi);
	font-family: "Avenir Next", Avenir, "Hiragino Kaku Gothic ProN", "Yu Gothic", sans-serif;
	line-height: 1.68;
}

main { width: min(720px, calc(100% - 36px)); margin: 0 auto; padding: 64px 0 88px; }
header { padding-bottom: 30px; border-bottom: 3px solid var(--sumi); }
.eyebrow { margin-bottom: 1.1rem; color: var(--vermilion); font-size: .78rem; font-weight: 700; letter-spacing: .035em; }

h1, h2, h3 {
	margin: 0 0 .65rem;
	font-family: "Hiragino Mincho ProN", "Yu Mincho", serif;
	font-weight: 600;
	line-height: 1.2;
}
h1 { font-size: clamp(2.5rem, 8vw, 4.75rem); font-weight: 500; letter-spacing: -.05em; line-height: 1.05; }
h2 { font-size: clamp(1.5rem, 4vw, 1.9rem); }
h3 { font-size: 1.08rem; }
p { margin: .45rem 0 1rem; }
.lede { max-width: 59ch; margin-bottom: 0; color: var(--ink-soft); font-size: 1.08rem; }
.muted { color: var(--ink-soft); }

section { margin: 0; padding: 34px 0; border-bottom: 1px solid var(--rule); }
.card, .callout, .quiz { padding: 21px; border: 1px solid var(--rule); background: var(--surface); }
.callout { border-left: 4px solid var(--moss); background: var(--mist); }
.mistake { border-left-color: var(--vermilion); background: var(--warm); }

table { width: 100%; border-collapse: collapse; font-size: .94rem; }
th, td { padding: .7rem .5rem; border-bottom: 1px solid var(--rule); text-align: left; vertical-align: top; }
th { color: var(--ink-soft); font-size: .77rem; letter-spacing: .045em; }
.jp { font-family: "Hiragino Kaku Gothic ProN", "Yu Gothic", Meiryo, sans-serif; font-size: 1.04em; }
ruby rt { color: var(--ink-soft); font-size: .6em; }
code { padding: .1em .3em; border-radius: 2px; background: var(--mist); }

.choices { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 10px; }
button {
	appearance: none;
	cursor: pointer;
	padding: .45rem .82rem;
	border: 1px solid var(--moss);
	border-radius: 2px;
	background: transparent;
	color: var(--moss);
	font: 700 .95rem "Avenir Next", Avenir, "Hiragino Kaku Gothic ProN", "Yu Gothic", sans-serif;
}
button:hover, button:focus-visible { background: var(--moss); color: white; outline: 3px solid var(--mist); outline-offset: 2px; }
.feedback { min-height: 1.6em; margin: .65rem 0 0; font-size: .92rem; }
.answer { display: none; margin-top: .6rem; color: var(--moss); }
.answer.show { display: block; }
.quiz + .quiz { margin-top: 14px; }

footer { margin-top: 44px; padding-top: 18px; border-top: 1px solid var(--rule); color: var(--ink-soft); font-size: .86rem; }
a { color: var(--moss); text-underline-offset: .2em; }
a:hover, a:focus-visible { color: var(--vermilion); }

@media (max-width: 560px) {
	main { padding-top: 38px; }
	.card, .callout, .quiz { padding: 17px; }
}

@media print {
	body { background: white; }
	main { width: 100%; margin: 0; padding: 0; }
	button, .feedback { display: none; }
	.answer { display: block; }
}