/* Layout: 단일 컬럼 문서형. 상단 고정 헤더, 섹션마다 좌측 라벨 + 우측 본문 그리드. 장식은 히어로의 하악운동 도해 하나뿐. */
:root {
  /* 기본 테마: 어두운 배경 + 밝은 글씨 (사용자 요청) */
  --bg: #0e141a;          /* 깊은 청회색 */
  --surface: #151d25;
  --ink: #e8edf2;         /* 밝은 본문 글씨 */
  --muted: #9aa7b4;
  --line: #27323d;
  --accent: #ff6b86;      /* 교합지(articulating paper) 레드 */
  --accent-2: #7fa6ff;    /* 교합지 블루 */
  --ph-bg: #2a1820;
  --font-display: "Noto Serif KR", "Noto Serif", Georgia, serif;
  --font-body: "IBM Plex Sans KR", "Apple SD Gothic Neo", "Malgun Gothic", system-ui, sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, Menlo, monospace;
  --step--1: .8125rem; --step-0: 1rem; --step-1: 1.25rem; --step-2: 1.625rem; --step-3: 2.25rem; --step-4: clamp(2.25rem, 5vw, 3.5rem);
  color-scheme: dark;
}

* { box-sizing: border-box }
html { scroll-behavior: smooth; scroll-padding-top: 80px }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto } }
body { background: var(--bg); color: var(--ink); font-family: var(--font-body); font-size: var(--step-0); line-height: 1.7; word-break: keep-all; overflow-wrap: anywhere }
a { color: inherit }
a:focus-visible, button:focus-visible { outline: 2px solid var(--accent-2); outline-offset: 3px; border-radius: 2px }
h1, h2, h3 { font-family: var(--font-display); line-height: 1.3; text-wrap: balance; margin: 0 }
p { margin: 0 }
.wrap { max-width: 1120px; margin-inline: auto; padding-inline: 20px }

/* header */
.top { position: sticky; top: env(safe-area-inset-top, 0px); z-index: 10; background: color-mix(in srgb, var(--bg) 92%, transparent); backdrop-filter: blur(8px); border-bottom: 1px solid var(--line) }
.top .wrap { display: flex; align-items: center; gap: 24px; padding-block: 14px; flex-wrap: wrap }
.brand { display: flex; align-items: baseline; gap: 8px; text-decoration: none }
.brand b { font-family: var(--font-display); font-size: 1.5rem; letter-spacing: .04em }
.brand span { font-family: var(--font-mono); font-size: .6875rem; letter-spacing: .14em; text-transform: uppercase; color: var(--muted) }
.nav { display: flex; gap: 20px; flex-wrap: wrap; margin-left: auto; font-size: .9375rem }
.nav a { text-decoration: none; color: var(--muted) }
.nav a:hover { color: var(--ink) }
/* 언어 선택: 지구본 버튼 + 팝업 메뉴 */
[hidden] { display: none !important }
.lang { position: relative }
.lang-btn { display: grid; place-items: center; width: 40px; height: 40px; border-radius: 10px; border: 1.5px solid transparent; background: none; color: var(--muted); cursor: pointer }
.lang-btn:hover { color: var(--ink); background: var(--surface) }
.lang-btn[aria-expanded="true"] { color: var(--ink); border-color: var(--accent-2) }
.lang-menu { position: absolute; right: 0; top: calc(100% + 10px); z-index: 20; min-width: 200px; display: grid; padding: 6px; background: var(--surface); border: 1px solid var(--line); border-radius: 14px; box-shadow: 0 16px 40px rgb(0 0 0 / .45) }
.lang-title { font-size: .8125rem; font-weight: 500; color: var(--muted); padding: 8px 12px 4px }
.lang-menu button { display: flex; align-items: center; justify-content: space-between; gap: 24px; width: 100%; padding: 10px 12px; border: 0; border-radius: 8px; background: none; color: var(--ink); font-family: var(--font-body); font-size: 1rem; text-align: left; cursor: pointer }
.lang-menu button:hover, .lang-menu button:focus-visible { background: color-mix(in srgb, var(--ink) 8%, transparent); outline-offset: -2px }
.lang-menu button svg { color: var(--accent-2); visibility: hidden; flex: none }
.lang-menu button[aria-checked="true"] { color: var(--accent-2); font-weight: 600 }
.lang-menu button[aria-checked="true"] svg { visibility: visible }
@media (max-width: 760px) { .nav { order: 3; width: 100%; margin-left: 0; gap: 14px; font-size: .875rem } .lang { margin-left: auto } }

/* 언어별 글꼴: 한글 기본, 일·중·러는 각 문자에 맞는 글꼴 우선 */
:lang(ja) { --font-display: "Noto Serif JP", serif; --font-body: "Noto Sans JP", "Hiragino Sans", "Yu Gothic", system-ui, sans-serif }
:lang(zh) { --font-display: "Noto Serif SC", serif; --font-body: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif }
:lang(ru), :lang(en) { --font-display: "Noto Serif", Georgia, serif; --font-body: "IBM Plex Sans", system-ui, sans-serif }
:lang(ja) body, :lang(zh) body { word-break: normal; line-break: strict }

/* placeholder chip */
.ph { display: inline-block; font: 500 .6875rem/1.4 var(--font-mono); letter-spacing: .08em; text-transform: uppercase; color: var(--accent); background: var(--ph-bg); border: 1px dashed var(--accent); border-radius: 3px; padding: 1px 6px; vertical-align: middle; white-space: nowrap }
.ph-block { border: 1px dashed var(--line); border-radius: 6px; padding: 16px; color: var(--muted); font-size: .9375rem; display: grid; gap: 6px }

/* hero */
.hero .wrap { display: grid; grid-template-columns: 1.15fr .85fr; gap: 48px; align-items: center; padding-block: 72px 56px }
.hero .wrap > * { min-width: 0 }
.eyebrow { font: 500 .75rem var(--font-mono); letter-spacing: .14em; text-transform: uppercase; color: var(--muted); display: flex; gap: 10px; align-items: center; flex-wrap: wrap }
.hero h1 { font-size: var(--step-4); font-weight: 700; margin-block: 18px 20px }
.hero h1 em { font-style: normal; color: var(--accent) }
.hero .lede { font-size: var(--step-1); color: var(--muted); max-width: 34em; line-height: 1.65 }
.cta { display: flex; gap: 12px; flex-wrap: wrap; margin-top: 32px }
.btn { display: inline-block; text-decoration: none; padding: 11px 20px; border-radius: 6px; font-weight: 600; font-size: .9375rem; border: 1px solid var(--ink) }
.btn.primary { background: var(--ink); color: var(--bg) }
.btn:hover { border-color: var(--accent); }
.diagram { background: var(--surface); border: 1px solid var(--line); border-radius: 8px; padding: 20px }
.diagram svg { width: 100%; height: auto; display: block }
.diagram figcaption { font: .75rem/1.5 var(--font-mono); color: var(--muted); margin-top: 10px }
@media (max-width: 860px) { .hero .wrap { grid-template-columns: 1fr; padding-block: 48px 40px } .diagram { max-width: 420px } }

/* sections */
section.block { border-top: 1px solid var(--line) }
section.block .wrap { display: grid; grid-template-columns: 220px 1fr; gap: 40px; padding-block: 64px }
section.block .wrap > * { min-width: 0 }
.label { font: 500 .75rem var(--font-mono); letter-spacing: .14em; text-transform: uppercase; color: var(--muted); padding-top: 8px }
.label b { display: block; font-family: var(--font-display); font-size: var(--step-2); letter-spacing: 0; text-transform: none; color: var(--ink); margin-top: 6px; font-weight: 700 }
.body { display: grid; gap: 28px }
.body > p { max-width: 40em; font-size: 1.0625rem }
@media (max-width: 760px) { section.block .wrap { grid-template-columns: 1fr; gap: 20px; padding-block: 48px } }

/* facts */
.facts { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1px; background: var(--line); border: 1px solid var(--line); border-radius: 6px; overflow: hidden }
.facts div { background: var(--surface); padding: 16px; display: grid; gap: 4px; align-content: start }
.facts dt { font: .6875rem var(--font-mono); letter-spacing: .1em; text-transform: uppercase; color: var(--muted) }
.facts dd { margin: 0; font-weight: 600 }
@media (max-width: 560px) { .facts { grid-template-columns: 1fr } }

/* process */
.steps { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(3, 1fr); gap: 0; border-top: 2px solid var(--ink) }
.steps li { padding: 20px 20px 4px 0; display: grid; gap: 10px; align-content: start }
.steps li + li { padding-left: 20px; border-left: 1px solid var(--line) }
.steps .n { font: 500 .8125rem var(--font-mono); color: var(--accent) }
.steps h3 { font-size: var(--step-1) }
.steps p { color: var(--muted); font-size: .9375rem }
.steps .terms { font: .75rem/1.6 var(--font-mono); color: var(--accent-2) }
@media (max-width: 760px) { .steps { grid-template-columns: 1fr } .steps li + li { padding-left: 0; border-left: 0; border-top: 1px solid var(--line) } }

/* seminars */
.courses { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px }
.course { background: var(--surface); border: 1px solid var(--line); border-radius: 8px; padding: 20px; display: grid; gap: 12px; grid-template-rows: auto auto 1fr auto }
.course .lvl { font: 500 .6875rem var(--font-mono); letter-spacing: .12em; text-transform: uppercase; color: var(--accent-2) }
.course h3 { font-size: 1.1875rem }
.course p { font-size: .9375rem; color: var(--muted) }
.course dl { margin: 0; display: grid; grid-template-columns: auto 1fr; gap: 4px 12px; font-size: .8125rem; border-top: 1px solid var(--line); padding-top: 12px }
.course dt { font-family: var(--font-mono); color: var(--muted) }
.course dd { margin: 0 }
@media (max-width: 900px) { .courses { grid-template-columns: 1fr } }
.format { display: flex; flex-wrap: wrap; gap: 8px }
.format span { border: 1px solid var(--line); border-radius: 999px; padding: 4px 12px; font-size: .875rem }

/* regions */
.regions { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(5, 1fr); gap: 1px; background: var(--line); border: 1px solid var(--line); border-radius: 6px; overflow: hidden }
.regions li { background: var(--surface); padding: 16px; display: grid; gap: 6px; align-content: start }
.regions .code { font: 500 .75rem var(--font-mono); color: var(--accent) }
.regions strong { font-size: 1.0625rem }
@media (max-width: 860px) { .regions { grid-template-columns: repeat(2, 1fr) } }
@media (max-width: 420px) { .regions { grid-template-columns: 1fr } }

/* news */
.news { list-style: none; margin: 0; padding: 0; display: grid }
.news li { display: grid; grid-template-columns: 110px 1fr; gap: 16px; padding-block: 14px; border-bottom: 1px solid var(--line); align-items: baseline }
.news time { font: .8125rem var(--font-mono); color: var(--muted); font-variant-numeric: tabular-nums }
.news span:last-child { color: var(--muted) }

/* contact */
.contact { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px }
.contact > div { background: var(--surface); border: 1px solid var(--line); border-radius: 8px; padding: 20px; display: grid; gap: 8px; align-content: start }
.contact h3 { font-size: 1.0625rem }
.contact .mono { font-family: var(--font-mono); font-size: .9375rem; user-select: all }
@media (max-width: 640px) { .contact { grid-template-columns: 1fr } }

footer { border-top: 1px solid var(--line); color: var(--muted); font-size: .8125rem }
footer .wrap { display: flex; flex-wrap: wrap; gap: 12px 24px; justify-content: space-between; padding-block: 28px }