: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(760px, calc(100% - 36px)); margin: 0 auto; padding: 64px 0 88px; }
header { padding-bottom: 30px; border-bottom: 3px solid var(--sumi); }

.eyebrow, .time, button, input, textarea, .feedback {
	font-family: "Avenir Next", Avenir, "Hiragino Kaku Gothic ProN", "Yu Gothic", sans-serif;
}
.eyebrow, .time { color: var(--vermilion); font-size: .78rem; font-weight: 700; letter-spacing: .035em; }
.eyebrow { margin-bottom: 1.1rem; }

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(2.8rem, 9vw, 5.4rem); font-weight: 500; letter-spacing: -.05em; line-height: 1; }
h2 { font-size: clamp(1.55rem, 4vw, 2rem); }
h3 { font-size: 1.1rem; }
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); }
.jp { font-family: "Hiragino Kaku Gothic ProN", "Yu Gothic", Meiryo, sans-serif; }
.time { display: block; margin-bottom: .65rem; }

section { margin: 0; padding: 36px 0; border-bottom: 1px solid var(--rule); }
.card, .dialogue, .drill { padding: 22px; border: 1px solid var(--rule); background: var(--surface); }
.dialogue p { display: grid; grid-template-columns: 2.25rem 1fr; gap: .45rem; margin: .7rem 0; }
.speaker { color: var(--vermilion); font-weight: 800; }
mark { background: var(--mist); color: inherit; padding: .08em .2em; }

table { width: 100%; border-collapse: collapse; font-size: .93rem; }
th, td { padding: .72rem .55rem; border-bottom: 1px solid var(--rule); text-align: left; vertical-align: top; }
th { color: var(--ink-soft); font-size: .76rem; letter-spacing: .045em; }

.mental-model, .naturalness { padding: 20px 22px; border-left: 4px solid var(--moss); background: var(--mist); }
.naturalness { border-left-color: var(--vermilion); background: var(--warm); }
.drill { margin-top: 16px; }
.prompt { margin-top: 1rem; padding-top: 1rem; border-top: 1px solid var(--rule); }

input[type="text"], textarea {
	width: 100%;
	padding: .72rem .8rem;
	border: 1px solid #9eaaa1;
	border-radius: 2px;
	background: white;
	color: var(--sumi);
	font-size: 1rem;
	line-height: 1.45;
}
textarea { min-height: 7rem; resize: vertical; }
button {
	cursor: pointer;
	margin-top: .6rem;
	padding: .52rem .88rem;
	border: 1px solid var(--moss);
	border-radius: 2px;
	background: transparent;
	color: var(--moss);
	font-weight: 700;
}
button:hover, button:focus-visible { background: var(--moss); color: white; outline: 3px solid var(--mist); outline-offset: 2px; }
.feedback { min-height: 1.4rem; margin: .55rem 0 0; font-size: .9rem; }
.answer, .model { display: none; }
.answer { margin-top: .75rem; color: var(--moss); }
.model { margin-top: 1rem; padding: 18px; border-left: 4px solid var(--moss); background: var(--mist); }
.answer.show, .model.show { display: block; }

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; }
	.dialogue p { grid-template-columns: 1.8rem 1fr; }
	.card, .dialogue, .drill { padding: 17px; }
}

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