/* Layout: sticky top bar, single reading column (max 920px), video sticks to the top of the lesson on wide screens */
:root {
  --bg: #f6f7f9;
  --surface: #ffffff;
  --fg: #1b2230;
  --muted: #5d6677;
  --line: #dde1e8;
  --blue: #1f4e8c;
  --red: #b8323a;
  --chip: #e8eef7;
  --good: #2e7d4f;
  --ko: "Gowun Batang", "Noto Serif KR", "Batang", serif;
  --ui: "IBM Plex Sans", "Noto Sans KR", system-ui, sans-serif;
}
/* Light is the default; dark only when the visitor picks it (data-theme set from localStorage) */
:root[data-theme="dark"] {
  --bg: #12161d; --surface: #1a2029; --fg: #e7ebf2; --muted: #9aa3b4; --line: #2b3340;
  --blue: #7fa8e6; --red: #ec6f76; --chip: #23304a; --good: #6fcf97; color-scheme: dark;
}
:root[data-theme="dark"] .video-wrap { box-shadow: 0 0 0 1px var(--line); }
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
/* keep-all stops Korean words from breaking mid-syllable-block; it does not affect Cyrillic */
body { margin: 0; background: var(--bg); color: var(--fg); font: 15px/1.55 var(--ui); word-break: keep-all; }
a { color: var(--blue); }
img { max-width: 100%; }
[hidden] { display: none !important; }
:focus-visible { outline: 2px solid var(--blue); outline-offset: 2px; }

header.site { position: sticky; top: 0; z-index: 20; background: var(--surface); border-bottom: 1px solid var(--line); padding-top: env(safe-area-inset-top, 0px); }
.site-in { max-width: 1100px; margin: 0 auto; display: flex; align-items: center; gap: 16px; flex-wrap: wrap;
  padding: 10px max(16px, env(safe-area-inset-right, 0px)) 10px max(16px, env(safe-area-inset-left, 0px)); }
.brand { display: flex; align-items: baseline; gap: 10px; text-decoration: none; color: var(--fg); }
.brand-ko { font-family: var(--ko); font-size: 24px; font-weight: 700; color: var(--blue); }
.brand-ru { font-size: 13px; color: var(--muted); }
.nav { display: flex; gap: 4px; flex-wrap: wrap; margin-left: auto; }
.nav a { text-decoration: none; color: var(--muted); padding: 6px 10px; border-radius: 8px; font-size: 14px; }
.nav a:hover { background: var(--chip); color: var(--fg); }
.nav a.on { background: var(--chip); color: var(--blue); font-weight: 600; }
.theme-btn { width: 38px; height: 38px; border-radius: 50%; border: 1px solid var(--line); background: var(--surface); color: var(--fg); cursor: pointer; display: grid; place-items: center; flex: none; }
.theme-btn:hover { border-color: var(--blue); color: var(--blue); }
.theme-btn svg { width: 18px; height: 18px; }

/* Phone: top bar keeps brand + theme toggle, sections move to a bottom tab bar */
.tabbar { display: none; }
@media (max-width: 760px) {
  .nav { display: none; }
  .theme-btn { margin-left: auto; }
  .site-in { padding-top: 8px; padding-bottom: 8px; }
  .brand-ko { font-size: 22px; }
  .tabbar {
    display: grid; grid-template-columns: repeat(6, 1fr); position: fixed; left: 0; right: 0; bottom: 0; z-index: 20;
    background: var(--surface); border-top: 1px solid var(--line);
    padding: 4px max(4px, env(safe-area-inset-right, 0px)) calc(4px + env(safe-area-inset-bottom, 0px)) max(4px, env(safe-area-inset-left, 0px));
  }
  .tabbar a { display: grid; justify-items: center; gap: 2px; padding: 6px 0; text-decoration: none; color: var(--muted); font-size: 10.5px; border-radius: 8px; min-width: 0; }
  .tabbar a svg { width: 22px; height: 22px; }
  .tabbar a.on { color: var(--blue); font-weight: 600; }
  .tabbar a span { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; max-width: 100%; }
  .foot { padding-bottom: calc(64px + env(safe-area-inset-bottom, 0px)); }
}

.page { max-width: 920px; margin: 0 auto; padding: 24px max(16px, env(safe-area-inset-right, 0px)) 64px max(16px, env(safe-area-inset-left, 0px)); outline: none; }
.foot { border-top: 1px solid var(--line); color: var(--muted); font-size: 13px; }
.foot-in { max-width: 920px; margin: 0 auto; padding: 20px max(16px, env(safe-area-inset-right, 0px)) calc(20px + env(safe-area-inset-bottom, 0px)) max(16px, env(safe-area-inset-left, 0px)); }

h1 { font-size: 28px; line-height: 1.25; margin: 0 0 6px; text-wrap: balance; }
h1 .ko, h2 .ko { font-family: var(--ko); color: var(--blue); font-weight: 700; margin-right: 10px; }
h2 { font-size: 20px; margin: 36px 0 10px; }
h3 { font-size: 16px; margin: 20px 0 8px; }
.lead { color: var(--muted); margin: 0 0 16px; max-width: 65ch; }
.eyebrow { font-size: 12px; letter-spacing: .08em; text-transform: uppercase; color: var(--muted); }

/* Course map on the home page */
.lessons { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 12px; }
.lcard { display: grid; gap: 4px; padding: 14px 16px; background: var(--surface); border: 1px solid var(--line); border-radius: 12px; text-decoration: none; color: var(--fg); }
.lcard:hover { border-color: var(--blue); }
.lcard .num { font-size: 12px; color: var(--muted); display: flex; justify-content: space-between; }
.lcard .t-ko { font-family: var(--ko); font-size: 20px; color: var(--blue); }
.lcard .gr { font-size: 13px; color: var(--muted); }
.done-badge { color: var(--good); font-weight: 600; }
.bar-progress { height: 6px; background: var(--chip); border-radius: 99px; overflow: hidden; margin: 8px 0 20px; max-width: 420px; }
.bar-progress span { display: block; height: 100%; background: var(--blue); }

/* Video */
.video-wrap { position: relative; aspect-ratio: 16 / 9; width: 100%; background: #000; border-radius: 12px; overflow: hidden; }
.video-wrap > div, .video-wrap iframe { position: absolute; inset: 0; width: 100%; height: 100%; border: 0; }
.parts { display: flex; gap: 8px; flex-wrap: wrap; margin: 10px 0; }
.chipbtn { font: inherit; font-size: 13px; padding: 5px 12px; border-radius: 99px; border: 1px solid var(--line); background: var(--surface); color: var(--fg); cursor: pointer; }
.chipbtn:hover { border-color: var(--blue); color: var(--blue); }
a.chipbtn { text-decoration: none; display: inline-block; }
.chipbtn.on { background: var(--blue); border-color: var(--blue); color: #fff; }
.video-note { font-size: 13px; color: var(--muted); }

/* Tables and phrase rows */
.tbl-wrap { overflow-x: auto; }
table { border-collapse: collapse; width: 100%; background: var(--surface); border: 1px solid var(--line); border-radius: 10px; overflow: hidden; font-size: 14px; }
th, td { text-align: left; padding: 8px 12px; border-top: 1px solid var(--line); vertical-align: top; }
th { background: var(--chip); font-weight: 600; border-top: 0; }
.rows { list-style: none; margin: 0; padding: 0; background: var(--surface); border: 1px solid var(--line); border-radius: 10px; }
.rows li { display: grid; grid-template-columns: 40px minmax(0, 1fr) minmax(0, 1fr); gap: 12px; align-items: center; padding: 8px 12px; border-top: 1px solid var(--line); }
.rows li:first-child { border-top: 0; }
.rows li.hit { background: var(--chip); }
.k { font-family: var(--ko); font-size: 18px; line-height: 1.35; overflow-wrap: anywhere; }
.who { font-family: var(--ui); font-size: 12px; color: var(--muted); margin-right: 6px; }
.r { color: var(--muted); overflow-wrap: anywhere; }
@media (max-width: 560px) {
  .rows li { grid-template-columns: 40px minmax(0, 1fr); }
  .rows li .r { grid-column: 2; margin-top: -6px; }
}
.say { width: 36px; height: 36px; border-radius: 50%; border: 1px solid var(--line); background: var(--surface); color: var(--blue); cursor: pointer; display: inline-grid; place-items: center; flex: none; }
.say:hover { border-color: var(--blue); }
.say.playing { background: var(--red); border-color: var(--red); color: #fff; }
.say svg { width: 18px; height: 18px; }
.say.sm { width: 28px; height: 28px; vertical-align: middle; }
.say.sm svg { width: 14px; height: 14px; }
.toolbar { display: flex; gap: 8px 12px; flex-wrap: wrap; align-items: center; margin: 8px 0 12px; }
.toolbar input[type=search] { flex: 1 1 220px; min-width: 0; font: inherit; padding: 8px 12px; border-radius: 8px; border: 1px solid var(--line); background: var(--surface); color: var(--fg); }
.toolbar select { font: inherit; font-size: 13px; padding: 6px 8px; border-radius: 8px; border: 1px solid var(--line); background: var(--surface); color: var(--fg); }
.toolbar label { font-size: 13px; color: var(--muted); display: inline-flex; gap: 6px; align-items: center; }
.masked { color: transparent !important; background: var(--chip); border-radius: 6px; cursor: pointer; user-select: none; }

/* Tasks */
.tasks { list-style: none; margin: 0; padding: 0; display: grid; gap: 8px; }
.task { background: var(--surface); border: 1px solid var(--line); border-radius: 10px; padding: 10px 14px; }
.task-head { display: flex; gap: 10px; align-items: flex-start; }
.task-head input[type=checkbox] { margin-top: 4px; width: 18px; height: 18px; accent-color: var(--blue); flex: none; }
.task-n { font-weight: 600; margin-right: 6px; white-space: nowrap; }
.task.done { opacity: .7; }
.task-actions { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 8px; padding-left: 28px; }
.answer { margin-top: 8px; margin-left: 28px; padding: 8px 12px; border-left: 3px solid var(--good); background: var(--chip); border-radius: 6px; }
.answer .script { color: var(--muted); font-size: 13px; margin-top: 4px; font-family: var(--ko); }
.note { background: var(--surface); border: 1px solid var(--line); border-left: 3px solid var(--blue); border-radius: 8px; padding: 10px 14px; margin: 12px 0; }
ul.plain { padding-left: 20px; }
ul.plain li { margin: 4px 0; }
.grid2 { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 12px; }
.pager { display: flex; justify-content: space-between; gap: 12px; margin-top: 40px; flex-wrap: wrap; }
.pager a { text-decoration: none; padding: 10px 14px; border: 1px solid var(--line); border-radius: 10px; background: var(--surface); }
.pager a:hover { border-color: var(--blue); }
.voice-warn { font-size: 13px; padding: 8px 12px; background: var(--chip); border-radius: 8px; margin: 8px 0; }
/* Lesson switcher strip */
.lstrip { display: flex; gap: 6px; overflow-x: auto; scrollbar-width: none; margin: 0 0 14px; padding-bottom: 2px; }
.lstrip::-webkit-scrollbar { display: none; }
.lstrip a { flex: none; min-width: 36px; height: 36px; display: grid; place-items: center; padding: 0 10px; border-radius: 10px; border: 1px solid var(--line); background: var(--surface); color: var(--fg); text-decoration: none; font-size: 14px; }
.lstrip a.on { background: var(--blue); border-color: var(--blue); color: #fff; }
.lstrip a.done:not(.on) { border-color: var(--good); color: var(--good); }

@media (max-width: 760px) {
  .page { padding-top: 16px; padding-bottom: 40px; }
  h1 { font-size: 23px; }
  h1 .ko { display: block; margin: 0 0 2px; }
  h2 { font-size: 18px; margin-top: 28px; display: flex; flex-wrap: wrap; align-items: center; gap: 8px; }
  .lead { font-size: 14.5px; }
  /* Video and chip rows run edge to edge on phones */
  .video-wrap { border-radius: 0; margin-left: calc(-1 * max(16px, env(safe-area-inset-left, 0px))); margin-right: calc(-1 * max(16px, env(safe-area-inset-right, 0px))); width: auto; }
  .parts { flex-wrap: nowrap; overflow-x: auto; scrollbar-width: none; margin-left: calc(-1 * max(16px, env(safe-area-inset-left, 0px))); margin-right: calc(-1 * max(16px, env(safe-area-inset-right, 0px))); padding: 0 max(16px, env(safe-area-inset-right, 0px)) 2px max(16px, env(safe-area-inset-left, 0px)); }
  .parts::-webkit-scrollbar { display: none; }
  .chipbtn { flex: none; padding: 7px 12px; }
  .rows li { padding: 10px 12px; gap: 10px; }
  .k { font-size: 17px; }
  .say { width: 40px; height: 40px; }
  .task { padding: 10px 12px; }
  .task-actions { padding-left: 0; }
  .answer { margin-left: 0; }
  th, td { padding: 7px 10px; }
  .lessons { grid-template-columns: 1fr; }
  .toolbar input[type=search] { flex-basis: 100%; }
  .pager a { flex: 1; text-align: center; }
}
@media (prefers-reduced-motion: no-preference) { .say, .chipbtn, .lcard, .theme-btn { transition: border-color .15s, background .15s, color .15s; } }