/*fluid-rem-v1*/html{font-size:clamp(16px,0.45vw + 10.4px,26px)}
/* ════════════════════════════════════════════════════════════
   Trí Lữ Nihongo — JLPT Study · Editorial Luxury
   Shared stylesheet for: khoa-hoc.html · chon-bai.html · bai-hoc.html
   ────────────────────────────────────────────────────────────
   Palette
     cream      #FBF6E8   nền giấy
     navy       #1B3A6B   tiêu đề · điểm nhấn chính
     navy-deep  #0F2547   nền khối đậm
     gold       #B89568   hairline · accent đồng
     ink        #0A1530   mực — chữ thân
     sumi       #8B3A2E   chữ Hán · nhấn hiếm
   Type
     Cormorant Garamond italic — display serif
     Inter Tight                — body
     JetBrains Mono             — nhãn uppercase
     Noto Serif JP              — chữ Nhật
   ════════════════════════════════════════════════════════════ */

:root {
  --cream:    #FBF6E8;
  --cream-2:  #F4EDD8;
  --cream-3:  #EFE6CE;
  --navy:     #1B3A6B;
  --navy-deep:#0F2547;
  --gold:     #B89568;
  --gold-soft:#D8C29B;
  --ink:      #0A1530;
  --sumi:     #8B3A2E;

  --ink-90: #0A1530E6;
  --ink-70: #0A1530B3;
  --ink-55: #0A15308C;
  --ink-40: #0A153066;
  --ink-15: #0A153026;
  --ink-08: #0A153014;
  --navy-60:#1B3A6B99;
  --navy-15:#1B3A6B26;
  --gold-50:#B8956880;
  --gold-30:#B895684D;
  --gold-12:#B895681F;

  --serif: "Cormorant Garamond", "EB Garamond", Georgia, serif;
  --sans:  "Inter Tight", "Inter", system-ui, -apple-system, sans-serif;
  --mono:  "JetBrains Mono", ui-monospace, "SFMono-Regular", Menlo, monospace;
  --jp:    "Noto Serif JP", "Shippori Mincho", serif;

  --col: 1180px;
  --col-wide: 1320px;
  --pad-x: clamp(22px, 5vw, 72px);
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
html { -webkit-font-smoothing: antialiased; -moz-osx-font-smoothing: grayscale; scroll-behavior: smooth; }

body {
  background: var(--cream);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 1rem;
  line-height: 1.6;
  font-weight: 400;
  letter-spacing: 0.004em;
  text-rendering: optimizeLegibility;
}

img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; cursor: pointer; background: none; border: 0; padding: 0; }
::selection { background: var(--gold); color: var(--cream); }
:focus-visible { outline: 2px solid var(--gold); outline-offset: 3px; }

/* ───────── Type ───────── */
.serif   { font-family: var(--serif); font-weight: 400; letter-spacing: -0.005em; }
.serif-i { font-family: var(--serif); font-weight: 400; font-style: italic; letter-spacing: -0.01em; }
.mono {
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  font-weight: 500;
}
.jp { font-family: var(--jp); font-weight: 400; }

.eyebrow {
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ink-55);
  font-weight: 500;
  display: inline-flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 4px 12px;
}
.eyebrow .num { color: var(--gold); }
.eyebrow .jp  { color: var(--gold); letter-spacing: 0.3em; }

.display {
  font-family: var(--serif);
  font-weight: 400;
  font-style: italic;
  font-size: clamp(44px, 6.6vw, 96px);
  line-height: 0.98;
  letter-spacing: -0.02em;
  color: var(--navy);
  text-wrap: balance;
  margin: 0;
}
.h1 {
  font-family: var(--serif);
  font-style: italic;
  font-weight: 400;
  font-size: clamp(36px, 4.8vw, 64px);
  line-height: 1.02;
  letter-spacing: -0.015em;
  color: var(--navy);
  text-wrap: balance;
  margin: 0;
}
.h2 {
  font-family: var(--serif);
  font-style: italic;
  font-weight: 400;
  font-size: clamp(28px, 3.4vw, 46px);
  line-height: 1.08;
  letter-spacing: -0.012em;
  color: var(--navy);
  text-wrap: balance;
  margin: 0;
}
.h3 {
  font-family: var(--serif);
  font-style: italic;
  font-weight: 400;
  font-size: clamp(20px, 2.2vw, 28px);
  line-height: 1.15;
  letter-spacing: -0.008em;
  color: var(--navy);
  margin: 0;
}
.lede {
  font-size: 1.125rem;
  line-height: 1.6;
  color: var(--ink-90);
  max-width: 54ch;
  font-weight: 350;
}
.body    { font-size: 1rem; line-height: 1.65; color: var(--ink-90); }
.body-sm { font-size: 0.875rem; line-height: 1.62; color: var(--ink-70); }

/* ───────── Layout ───────── */
.page { min-height: 100vh; padding-top: 78px; }
.section { padding: clamp(56px, 8vh, 120px) var(--pad-x); position: relative; }
.section-tight { padding: clamp(40px, 5vh, 72px) var(--pad-x); position: relative; }
.container { max-width: var(--col); margin: 0 auto; width: 100%; }
.container-wide { max-width: var(--col-wide); margin: 0 auto; width: 100%; }

.rule { height: 1px; background: var(--ink-15); border: 0; margin: 0; }
.rule-gold { background: var(--gold-30); }

/* ───────── Nav ───────── */
.site-nav {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 50;
  background: color-mix(in oklab, var(--cream) 92%, transparent);
  backdrop-filter: blur(18px) saturate(140%);
  -webkit-backdrop-filter: blur(18px) saturate(140%);
  border-bottom: 1px solid var(--gold-30);
}
.site-nav-in {
  max-width: var(--col-wide);
  margin: 0 auto;
  padding: 16px var(--pad-x);
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 24px;
}
.wordmark { display: flex; flex-direction: column; align-items: center; gap: 3px; cursor: pointer; }
.wordmark-main {
  font-family: var(--serif);
  font-style: italic;
  font-weight: 500;
  font-size: 1.625rem;
  letter-spacing: 0.005em;
  color: var(--navy);
  line-height: 1;
}
.wordmark-main .sep { font-style: normal; color: var(--gold); }
.wordmark-jp {
  font-family: var(--jp);
  font-size: 0.6875rem;
  letter-spacing: 0.42em;
  color: var(--gold);
  text-transform: uppercase;
}
.nav-crumb {
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ink-55);
  display: inline-flex;
  align-items: center;
  gap: 10px;
}
.nav-crumb .sep { color: var(--gold); }
.nav-crumb a { transition: color .3s ease; }
.nav-crumb a:hover { color: var(--gold); }
.nav-crumb .here { color: var(--navy); }
.nav-left { justify-self: start; }
.nav-right { justify-self: end; text-align: right; }
.nav-back {
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--navy);
  display: inline-flex;
  align-items: center;
  gap: 8px;
  transition: gap .3s ease, color .3s ease;
}
.nav-back:hover { gap: 13px; color: var(--gold); }

@media (max-width: 760px) {
  .site-nav-in { grid-template-columns: 1fr auto; gap: 14px; }
  .nav-left { display: none; }
  .wordmark { order: -1; align-items: flex-start; }
  .wordmark-main { font-size: 1.3125rem; }
  .page { padding-top: 66px; }
}

/* ───────── Buttons / links ───────── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 14px 24px;
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  background: var(--navy);
  color: var(--cream);
  transition: background .3s ease, transform .3s ease;
}
.btn:hover { background: var(--navy-deep); }
.btn .arr { transition: transform .3s ease; }
.btn:hover .arr { transform: translateX(4px); }
.btn-gold { background: var(--gold); color: var(--navy-deep); }
.btn-gold:hover { background: #a8804f; color: var(--cream); }
.btn-ghost { background: transparent; color: var(--navy); border: 1px solid var(--navy-15); }
.btn-ghost:hover { background: var(--ink-08); }

.link-line {
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--navy);
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding-bottom: 4px;
  border-bottom: 1px solid var(--navy);
  transition: gap .3s ease;
}
.link-line:hover { gap: 16px; }

/* ───────── Eyebrow header block ───────── */
.kicker-row {
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: 36px;
  align-items: baseline;
}
@media (max-width: 760px) { .kicker-row { grid-template-columns: 1fr; gap: 14px; } }

/* ════════════════════════════════════════════════════════════
   PAGE 1 — KHÓA HỌC
   ════════════════════════════════════════════════════════════ */

/* two big course blocks */
.course-blocks {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0;
  border: 1px solid var(--ink-15);
}
@media (max-width: 860px) { .course-blocks { grid-template-columns: 1fr; } }

.course-block {
  position: relative;
  overflow: hidden;
  padding: clamp(34px, 4vw, 56px);
  min-height: 360px;
  display: flex;
  flex-direction: column;
  isolation: isolate;
}
.course-block + .course-block { border-left: 1px solid var(--ink-15); }
@media (max-width: 860px) {
  .course-block + .course-block { border-left: 0; border-top: 1px solid var(--ink-15); }
}
.course-block .cb-wm {
  position: absolute;
  right: -3vw; top: 50%;
  transform: translateY(-50%);
  font-family: var(--jp);
  font-weight: 500;
  font-size: clamp(220px, 26vw, 360px);
  line-height: 0.78;
  pointer-events: none;
  user-select: none;
  z-index: -1;
}
.course-block.is-navy {
  background: var(--navy-deep);
  color: var(--cream);
}
.course-block.is-navy .cb-wm { color: color-mix(in oklab, var(--cream) 7%, transparent); }
.course-block.is-gold {
  background: linear-gradient(160deg, var(--cream-2), var(--cream-3));
  color: var(--ink);
}
.course-block.is-gold .cb-wm { color: color-mix(in oklab, var(--gold) 22%, transparent); }

.cb-top { display: flex; justify-content: space-between; align-items: baseline; gap: 14px; margin-bottom: auto; }
.cb-tag {
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
}
.is-navy .cb-tag { color: var(--gold-soft); }
.is-gold .cb-tag { color: var(--gold); }
.cb-level {
  font-family: var(--serif);
  font-style: italic;
  font-size: clamp(46px, 5vw, 68px);
  line-height: 1;
}
.is-navy .cb-level { color: var(--cream); }
.is-gold .cb-level { color: var(--navy); }

.cb-body { margin-top: clamp(28px, 4vw, 48px); }
.cb-title {
  font-family: var(--serif);
  font-style: italic;
  font-size: clamp(30px, 3.4vw, 44px);
  line-height: 1.04;
  letter-spacing: -0.012em;
  margin: 0 0 16px;
}
.is-navy .cb-title { color: var(--cream); }
.is-gold .cb-title { color: var(--navy); }
.cb-desc { font-size: 0.9062rem; line-height: 1.58; max-width: 34ch; margin: 0 0 26px; }
.is-navy .cb-desc { color: color-mix(in oklab, var(--cream) 78%, transparent); }
.is-gold .cb-desc { color: var(--ink-70); }

.cb-meta {
  display: flex;
  gap: 0;
  border-top: 1px solid;
  margin-bottom: 26px;
}
.is-navy .cb-meta { border-color: color-mix(in oklab, var(--cream) 16%, transparent); }
.is-gold .cb-meta { border-color: var(--ink-15); }
.cb-meta > div { padding: 14px 18px 0 0; }
.cb-meta > div + div { padding-left: 18px; border-left: 1px solid; }
.is-navy .cb-meta > div + div { border-color: color-mix(in oklab, var(--cream) 12%, transparent); }
.is-gold .cb-meta > div + div { border-color: var(--ink-08); }
.cb-meta-lab {
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  margin-bottom: 6px;
}
.is-navy .cb-meta-lab { color: color-mix(in oklab, var(--cream) 55%, transparent); }
.is-gold .cb-meta-lab { color: var(--ink-55); }
.cb-meta-val { font-family: var(--serif); font-style: italic; font-size: 1.1875rem; line-height: 1; }
.is-navy .cb-meta-val { color: var(--gold-soft); }
.is-gold .cb-meta-val { color: var(--navy); }

.cb-cta {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 13px 22px;
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  align-self: flex-start;
  transition: gap .3s ease, background .3s ease;
}
.is-navy .cb-cta { background: var(--gold); color: var(--navy-deep); }
.is-navy .cb-cta:hover { gap: 16px; background: var(--gold-soft); }
.is-gold .cb-cta { background: var(--navy); color: var(--cream); }
.is-gold .cb-cta:hover { gap: 16px; background: var(--navy-deep); }

/* module grid (8 học phần) */
.module-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  border-top: 1px solid var(--ink-15);
  border-left: 1px solid var(--ink-15);
}
@media (max-width: 980px) { .module-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 560px) { .module-grid { grid-template-columns: 1fr; } }

.module {
  position: relative;
  overflow: hidden;
  padding: 32px 28px 30px;
  border-right: 1px solid var(--ink-15);
  border-bottom: 1px solid var(--ink-15);
  min-height: 240px;
  display: flex;
  flex-direction: column;
  background: var(--cream);
  transition: background .4s ease;
}
.module:hover { background: var(--cream-2); }
.module-num {
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.18em;
  color: var(--ink-40);
  margin-bottom: 22px;
}
.module-kanji {
  font-family: var(--jp);
  font-weight: 500;
  font-size: 3.5rem;
  line-height: 1;
  color: var(--navy);
  margin-bottom: 18px;
  transition: color .4s ease, transform .4s ease;
}
.module:hover .module-kanji { color: var(--sumi); transform: translateY(-2px); }
.module-title {
  font-family: var(--serif);
  font-style: italic;
  font-size: 1.5625rem;
  line-height: 1.05;
  color: var(--navy);
  margin: 0 0 10px;
}
.module-desc { font-size: 0.7812rem; line-height: 1.55; color: var(--ink-70); margin: 0 0 18px; flex: 1; }
.module-foot {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--ink-40);
  padding-top: 14px;
  border-top: 1px solid var(--ink-08);
}
.module-foot .arr { color: var(--gold); transition: transform .3s ease; }
.module:hover .module-foot .arr { transform: translateX(4px); }

/* ════════════════════════════════════════════════════════════
   PAGE 2 — CHỌN BÀI
   ════════════════════════════════════════════════════════════ */

/* sub-module tabs (within a học phần) */
.chip-row { display: flex; flex-wrap: wrap; gap: 10px; }
.chip {
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  padding: 9px 16px;
  border: 1px solid var(--navy-15);
  color: var(--ink-70);
  background: transparent;
  transition: all .3s ease;
}
.chip:hover { border-color: var(--gold); color: var(--navy); }
.chip.active { background: var(--navy); color: var(--cream); border-color: var(--navy); }

.lesson-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border-top: 1px solid var(--ink-15);
  border-left: 1px solid var(--ink-15);
}
@media (max-width: 920px) { .lesson-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 580px) { .lesson-grid { grid-template-columns: 1fr; } }

.lesson-card {
  position: relative;
  overflow: hidden;
  padding: 28px 28px 24px;
  border-right: 1px solid var(--ink-15);
  border-bottom: 1px solid var(--ink-15);
  background: var(--cream);
  display: flex;
  flex-direction: column;
  min-height: 248px;
  transition: background .4s ease;
}
.lesson-card:hover { background: var(--cream-2); }
.lesson-card.is-done { background: color-mix(in oklab, var(--gold) 6%, var(--cream)); }
.lc-top { display: flex; align-items: baseline; justify-content: space-between; gap: 12px; margin-bottom: 18px; }
.lc-num {
  font-family: var(--serif);
  font-style: italic;
  font-size: 3.625rem;
  line-height: 0.82;
  color: var(--navy);
  letter-spacing: -0.02em;
}
.lc-num .small { font-size: 1.375rem; color: var(--gold); }
.lc-status {
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  padding: 4px 9px;
  white-space: nowrap;
}
.lc-status.done { background: var(--gold); color: var(--navy-deep); }
.lc-status.next { background: var(--navy); color: var(--cream); }
.lc-status.todo { color: var(--ink-40); border: 1px solid var(--ink-15); }
.lc-title {
  font-family: var(--serif);
  font-style: italic;
  font-size: 1.4375rem;
  line-height: 1.08;
  color: var(--navy);
  margin: 0 0 6px;
}
.lc-jp {
  font-family: var(--jp);
  font-size: 0.875rem;
  line-height: 1.7;
  color: var(--ink-70);
  margin: 0 0 auto;
  letter-spacing: 0.02em;
}
.lc-jp .em { color: var(--sumi); }
.lc-foot {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-40);
  padding-top: 16px;
  margin-top: 16px;
  border-top: 1px solid var(--ink-08);
}
.lc-foot .arr { color: var(--gold); transition: transform .3s ease; }
.lesson-card:hover .lc-foot .arr { transform: translateX(4px); }

/* progress strip */
.progress-strip {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  border: 1px solid var(--ink-15);
}
@media (max-width: 700px) { .progress-strip { grid-template-columns: repeat(2, 1fr); } }
.progress-strip > div { padding: 22px 24px; }
.progress-strip > div + div { border-left: 1px solid var(--ink-08); }
@media (max-width: 700px) {
  .progress-strip > div:nth-child(3) { border-left: 0; border-top: 1px solid var(--ink-08); }
  .progress-strip > div:nth-child(4) { border-top: 1px solid var(--ink-08); }
}
.ps-lab { font-family: var(--mono); font-size: 0.6875rem; letter-spacing: 0.16em; text-transform: uppercase; color: var(--ink-55); margin-bottom: 8px; }
.ps-val { font-family: var(--serif); font-style: italic; font-size: 1.875rem; line-height: 1; color: var(--navy); }
.ps-val .u { font-size: 0.9375rem; color: var(--gold); }

/* ════════════════════════════════════════════════════════════
   PAGE 3 — BÀI HỌC
   ════════════════════════════════════════════════════════════ */

.lesson-head {
  position: relative;
  overflow: hidden;
  padding: clamp(40px, 6vh, 76px) var(--pad-x) clamp(34px, 4vh, 52px);
  background: var(--navy-deep);
  color: var(--cream);
  isolation: isolate;
}
.lesson-head .lh-wm {
  position: absolute;
  right: -2vw; top: 50%;
  transform: translateY(-50%);
  font-family: var(--jp);
  font-weight: 500;
  font-size: clamp(200px, 24vw, 340px);
  line-height: 0.78;
  color: color-mix(in oklab, var(--cream) 6%, transparent);
  pointer-events: none;
  user-select: none;
  z-index: -1;
}
.lh-eyebrow {
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--gold-soft);
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 22px;
}
.lh-eyebrow .jp { color: color-mix(in oklab, var(--cream) 55%, transparent); letter-spacing: 0.28em; }
.lh-row { display: grid; grid-template-columns: auto 1fr; gap: clamp(24px, 4vw, 48px); align-items: end; }
@media (max-width: 680px) { .lh-row { grid-template-columns: 1fr; gap: 18px; } }
.lh-num {
  font-family: var(--serif);
  font-style: italic;
  font-size: clamp(72px, 12vw, 150px);
  line-height: 0.8;
  color: var(--gold-soft);
  letter-spacing: -0.03em;
}
.lh-num .lab { display: block; font-size: 0.75rem; letter-spacing: 0.2em; font-style: normal; font-family: var(--mono); color: color-mix(in oklab, var(--cream) 55%, transparent); margin-bottom: 12px; text-transform: uppercase; }
.lh-title {
  font-family: var(--serif);
  font-style: italic;
  font-size: clamp(34px, 4.6vw, 60px);
  line-height: 1.0;
  letter-spacing: -0.015em;
  color: var(--cream);
  margin: 0 0 12px;
}
.lh-jp { font-family: var(--jp); font-size: clamp(17px, 2vw, 22px); color: var(--gold-soft); letter-spacing: 0.06em; }
.lh-stats {
  display: flex;
  flex-wrap: wrap;
  gap: 28px;
  margin-top: 30px;
  padding-top: 24px;
  border-top: 1px solid color-mix(in oklab, var(--cream) 16%, transparent);
}
.lh-stat-lab { font-family: var(--mono); font-size: 0.6875rem; letter-spacing: 0.16em; text-transform: uppercase; color: color-mix(in oklab, var(--cream) 55%, transparent); margin-bottom: 6px; }
.lh-stat-val { font-family: var(--serif); font-style: italic; font-size: 1.375rem; color: var(--cream); line-height: 1; }

/* lesson sub-nav (back + prev/next) */
.lesson-bar {
  position: sticky;
  top: 78px;
  z-index: 30;
  background: color-mix(in oklab, var(--cream) 94%, transparent);
  backdrop-filter: blur(14px) saturate(140%);
  -webkit-backdrop-filter: blur(14px) saturate(140%);
  border-bottom: 1px solid var(--gold-30);
}
@media (max-width: 760px) { .lesson-bar { top: 66px; } }
.lesson-bar-in {
  max-width: var(--col-wide);
  margin: 0 auto;
  padding: 12px var(--pad-x);
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 16px;
}
.lb-nav {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--navy);
  padding: 8px 4px;
  transition: gap .3s ease, color .3s ease, opacity .3s ease;
}
.lb-prev { justify-self: start; }
.lb-next { justify-self: end; }
.lb-prev:hover { gap: 14px; color: var(--gold); }
.lb-next:hover { gap: 14px; color: var(--gold); }
.lb-center {
  justify-self: center;
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--ink-55);
  display: inline-flex;
  align-items: center;
  gap: 8px;
  transition: color .3s ease;
}
.lb-center:hover { color: var(--navy); }
.lb-center .ic { color: var(--gold); }
.lb-sub { display: block; font-family: var(--sans); font-style: normal; font-size: 0.6875rem; letter-spacing: 0; text-transform: none; color: var(--ink-40); margin-top: 2px; }
@media (max-width: 680px) {
  .lesson-bar-in { grid-template-columns: auto 1fr auto; }
  .lb-sub { display: none; }
  .lb-center { font-size: 0; gap: 0; }
  .lb-center .ic { font-size: 1rem; }
}

/* content tabs */
.tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 0;
  border-bottom: 1px solid var(--ink-15);
  margin-bottom: clamp(36px, 5vh, 56px);
}
.tab {
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  padding: 16px 22px;
  color: var(--ink-55);
  position: relative;
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  transition: color .3s ease;
}
.tab .jp { font-family: var(--jp); font-size: 0.75rem; color: var(--gold); }
.tab:hover { color: var(--navy); }
.tab.active { color: var(--navy); }
.tab.active::after { content: ""; position: absolute; left: 0; right: 0; bottom: -1px; height: 2px; background: var(--gold); }
.tab .ct { font-size: 0.6875rem; color: var(--ink-40); }

.tab-panel { display: none; }
.tab-panel.active { display: block; animation: fadeUp .5s cubic-bezier(.2,.7,.2,1); }
@keyframes fadeUp { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }

/* vocab cards */
.vocab-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 0; border-top: 1px solid var(--ink-15); border-left: 1px solid var(--ink-15); }
@media (max-width: 720px) { .vocab-grid { grid-template-columns: 1fr; } }
.vocab {
  padding: 28px 30px;
  border-right: 1px solid var(--ink-15);
  border-bottom: 1px solid var(--ink-15);
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 14px 20px;
  align-items: start;
  position: relative;
  background: var(--cream);
  transition: background .4s ease;
}
.vocab:hover { background: var(--cream-2); }
.vocab-idx { font-family: var(--mono); font-size: 0.6875rem; letter-spacing: 0.14em; color: var(--ink-40); grid-column: 1 / -1; }
.vocab-jp { font-family: var(--jp); font-size: 2.375rem; line-height: 1; color: var(--navy); }
.vocab-reading { font-family: var(--jp); font-size: 0.9375rem; color: var(--ink-55); margin-top: 6px; letter-spacing: 0.04em; }
.vocab-romaji { font-family: var(--mono); font-size: 0.6875rem; letter-spacing: 0.12em; color: var(--gold); margin-top: 8px; text-transform: lowercase; }
.vocab-vn { font-family: var(--serif); font-style: italic; font-size: 1.5625rem; color: var(--navy); text-align: right; line-height: 1.1; }
.vocab-type { font-family: var(--mono); font-size: 0.6875rem; letter-spacing: 0.16em; text-transform: uppercase; color: var(--ink-40); text-align: right; margin-top: 8px; }
.vocab-ex {
  grid-column: 1 / -1;
  padding-top: 16px;
  margin-top: 4px;
  border-top: 1px solid var(--ink-08);
}
.vocab-ex-jp { font-family: var(--jp); font-size: 1.0625rem; line-height: 2.2; color: var(--ink-90); }
.vocab-ex-jp .hl { color: var(--sumi); border-bottom: 1px solid var(--gold-50); }
.vocab-ex-jp ruby rt { font-family: var(--jp); font-size: 0.6875rem; color: var(--gold); font-weight: 500; letter-spacing: 0.02em; }
.vocab-ex-vn { font-size: 0.8438rem; color: var(--ink-55); margin-top: 6px; font-style: italic; font-family: var(--serif); }

/* grammar pattern cards */
.grammar { border-top: 1px solid var(--ink-15); }
.grammar-item {
  padding: clamp(28px, 4vw, 44px) 0;
  border-bottom: 1px solid var(--ink-15);
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: clamp(24px, 4vw, 56px);
  align-items: start;
}
@media (max-width: 760px) { .grammar-item { grid-template-columns: 1fr; gap: 18px; } }
.gr-pat-num { font-family: var(--mono); font-size: 0.6875rem; letter-spacing: 0.18em; color: var(--gold); margin-bottom: 16px; }
.gr-pattern { font-family: var(--jp); font-size: clamp(24px, 3vw, 34px); line-height: 1.2; color: var(--navy); }
.gr-pattern .p { color: var(--sumi); }
.gr-mean { font-family: var(--serif); font-style: italic; font-size: 1.1875rem; color: var(--ink-70); margin-top: 12px; line-height: 1.2; }
.gr-desc { font-size: 0.9375rem; line-height: 1.65; color: var(--ink-90); margin: 0 0 22px; max-width: 60ch; }
.gr-ex { border-top: 1px solid var(--ink-15); }
.gr-ex-row {
  display: grid;
  grid-template-columns: 20px 1fr;
  gap: 16px;
  padding: 16px 0;
  border-bottom: 1px solid var(--ink-08);
  align-items: baseline;
}
.gr-ex-dot { color: var(--gold); font-size: 0.6875rem; line-height: 1.8; }
.gr-ex-jp { font-family: var(--jp); font-size: 1.0625rem; line-height: 2.2; color: var(--ink-90); }
.gr-ex-jp .hl { color: var(--sumi); border-bottom: 1px solid var(--gold-50); }
.gr-ex-jp ruby rt { font-family: var(--jp); font-size: 0.6875rem; color: var(--gold); font-weight: 500; letter-spacing: 0.02em; }
.gr-ex-vn { font-size: 0.8438rem; color: var(--ink-55); margin-top: 5px; font-family: var(--serif); font-style: italic; }

/* grammar note / warning / tip blocks */
.gr-note {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 14px 18px;
  border-radius: 0 10px 10px 0;
  margin-bottom: 20px;
  font-size: 0.875rem;
  line-height: 1.6;
  color: var(--ink-90);
}
.gr-note-tip  { background: var(--gold-08); border-left: 2px solid var(--gold); }
.gr-note-warn { background: color-mix(in oklab, var(--sumi) 6%, transparent); border-left: 2px solid var(--sumi); }
.gr-note-icon { font-family: var(--jp); font-size: 0.9375rem; flex-shrink: 0; line-height: 1.6; }
.gr-note-tip  .gr-note-icon { color: var(--gold); }
.gr-note-warn .gr-note-icon { color: var(--sumi); }
.gr-note-body strong { font-weight: 600; color: var(--navy); }
.gr-note-body .jp { font-size: 0.9375rem; }

/* grammar exercises */
.gr-exercises {
  margin-top: clamp(28px, 4vh, 44px);
  padding-top: clamp(24px, 3vh, 36px);
  border-top: 2px solid var(--gold-30);
}
.gr-ex-title {
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--gold);
  margin-bottom: 22px;
  display: flex;
  align-items: center;
  gap: 10px;
}
.gr-ex-title .jp { font-family: var(--jp); font-size: 0.75rem; color: var(--ink-40); letter-spacing: 0.08em; }

.ex-item {
  padding: clamp(20px, 2.5vw, 30px);
  background: var(--cream-2);
  border: 1px solid var(--ink-08);
  border-radius: 12px;
  margin-bottom: 14px;
  transition: border-color .3s ease;
}
.ex-item:hover { border-color: var(--gold-30); }
.ex-item-q {
  font-family: var(--jp);
  font-size: 1.0625rem;
  line-height: 2.0;
  color: var(--ink-90);
  margin-bottom: 14px;
}
.ex-item-q ruby rt { font-family: var(--jp); font-size: 0.6875rem; color: var(--gold); font-weight: 500; }
.ex-item-q .blank {
  display: inline-block;
  min-width: 80px;
  border-bottom: 2px solid var(--navy);
  margin: 0 4px;
  vertical-align: bottom;
  line-height: 1;
}
.ex-choices {
  display: flex;
  flex-wrap: wrap;
  gap: 9px;
  margin-bottom: 14px;
}
.ex-choice {
  font-family: var(--jp);
  font-size: 0.9375rem;
  padding: 8px 18px;
  border: 1px solid var(--navy-15);
  border-radius: 20px;
  color: var(--navy);
  background: var(--cream);
  cursor: pointer;
  transition: all .25s ease;
  user-select: none;
}
.ex-choice:hover { border-color: var(--gold); background: var(--gold-08); }
.ex-choice.selected { background: var(--navy); color: var(--cream); border-color: var(--navy); }
.ex-choice.correct  { background: #1e6b42; color: var(--cream); border-color: #1e6b42; }
.ex-choice.wrong    { background: var(--sumi); color: var(--cream); border-color: var(--sumi); }
.ex-reveal {
  display: none;
  padding: 12px 16px;
  background: var(--cream);
  border-left: 2px solid var(--gold);
  border-radius: 0 10px 10px 0;
  font-size: 0.875rem;
  line-height: 1.6;
  color: var(--ink-90);
  margin-top: 8px;
}
.ex-reveal.show { display: block; }
.ex-reveal .jp { font-family: var(--jp); font-size: 0.9375rem; }
.ex-reveal strong { color: var(--navy); }

/* translate exercise */
.ex-translate-input {
  width: 100%;
  background: var(--cream);
  border: 1px solid var(--ink-15);
  border-radius: 8px;
  padding: 10px 14px;
  font-family: var(--jp);
  font-size: 1rem;
  color: var(--ink);
  outline: none;
  transition: border-color .3s ease;
  margin-bottom: 10px;
}
.ex-translate-input:focus { border-color: var(--gold-50); }
.ex-btn-check {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 22px;
  background: var(--navy);
  color: var(--cream);
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  border-radius: 6px;
  cursor: pointer;
  transition: background .3s ease;
  border: 0;
}
.ex-btn-check:hover { background: var(--navy-deep); }

/* kanji cards (Hán tự tab) */
.kanji-grid { display: grid; grid-template-columns: repeat(3, 1fr); border-top: 1px solid var(--ink-15); border-left: 1px solid var(--ink-15); }
@media (max-width: 820px) { .kanji-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 540px) { .kanji-grid { grid-template-columns: 1fr; } }
.kanji-cell {
  padding: 30px;
  border-right: 1px solid var(--ink-15);
  border-bottom: 1px solid var(--ink-15);
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 24px;
  align-items: center;
  background: var(--cream);
  transition: background .4s ease;
}
.kanji-cell:hover { background: var(--cream-2); }
.kanji-big { font-family: var(--jp); font-weight: 500; font-size: 76px; line-height: 1; color: var(--navy); }
.kanji-cell:hover .kanji-big { color: var(--sumi); }
.kanji-on { font-family: var(--jp); font-size: 0.8125rem; color: var(--sumi); letter-spacing: 0.08em; }
.kanji-kun { font-family: var(--jp); font-size: 0.8125rem; color: var(--ink-70); letter-spacing: 0.08em; margin-top: 3px; }
.kanji-vn { font-family: var(--serif); font-style: italic; font-size: 1.25rem; color: var(--navy); margin-top: 10px; }
.kanji-strokes { font-family: var(--mono); font-size: 0.6875rem; letter-spacing: 0.14em; text-transform: uppercase; color: var(--ink-40); margin-top: 10px; }

/* practice / footer cta on lesson page */
.lesson-cta {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border: 1px solid var(--ink-15);
}
@media (max-width: 760px) { .lesson-cta { grid-template-columns: 1fr; } }
.lcta {
  padding: 36px 32px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  transition: background .4s ease;
}
.lcta + .lcta { border-left: 1px solid var(--ink-15); }
@media (max-width: 760px) { .lcta + .lcta { border-left: 0; border-top: 1px solid var(--ink-15); } }
.lcta:hover { background: var(--cream-2); }
.lcta-jp { font-family: var(--jp); font-size: 1.875rem; color: var(--gold); line-height: 1; }
.lcta-title { font-family: var(--serif); font-style: italic; font-size: 1.5rem; color: var(--navy); }
.lcta-desc { font-size: 0.8125rem; color: var(--ink-70); line-height: 1.55; flex: 1; }
.lcta-link { font-family: var(--mono); font-size: 0.6875rem; letter-spacing: 0.16em; text-transform: uppercase; color: var(--navy); display: inline-flex; gap: 8px; align-items: center; }
.lcta:hover .lcta-link { color: var(--gold); }

/* ───────── Footer (compact) ───────── */
.foot {
  padding: clamp(48px, 7vh, 88px) var(--pad-x) 36px;
  border-top: 1px solid var(--ink-15);
}
.foot-in {
  max-width: var(--col-wide);
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  gap: 40px;
  flex-wrap: wrap;
}
.foot-brand .wm { font-family: var(--serif); font-style: italic; font-size: 1.875rem; color: var(--navy); line-height: 1; }
.foot-brand .jp { font-family: var(--jp); font-size: 0.6875rem; letter-spacing: 0.34em; color: var(--gold); text-transform: uppercase; margin-top: 8px; }
.foot-tag { font-family: var(--serif); font-style: italic; font-size: 1.0625rem; color: var(--gold); }
.foot-meta {
  max-width: var(--col-wide);
  margin: 36px auto 0;
  padding-top: 22px;
  border-top: 1px solid var(--ink-08);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 14px;
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-40);
}

/* ───────── Reveal ───────── */
.reveal { opacity: 0; transform: translateY(16px); transition: opacity .9s cubic-bezier(.2,.7,.2,1), transform .9s cubic-bezier(.2,.7,.2,1); will-change: opacity, transform; }
.reveal.in { opacity: 1; transform: translateY(0); }
.reveal[data-delay="1"] { transition-delay: .07s; }
.reveal[data-delay="2"] { transition-delay: .14s; }
.reveal[data-delay="3"] { transition-delay: .21s; }
.reveal[data-delay="4"] { transition-delay: .28s; }
.reveal[data-delay="5"] { transition-delay: .35s; }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: .001ms !important; transition-duration: .001ms !important; }
  .reveal { opacity: 1 !important; transform: none !important; }
  html { scroll-behavior: auto; }
}

/* small utility */
.mt-s { margin-top: clamp(36px, 5vh, 64px); }
.mt-m { margin-top: clamp(48px, 7vh, 88px); }