.ka-home,
.ka-hero,
.ka-progress,
.ka-lessons,
.ka-quiz,
.ka-demo,
.ka-cta {
  --ka-ink: var(--ink, #17384f);
  --ka-accent: var(--accent, #3485b7);
  --ka-line: var(--line, #d7e6ee);
  --ka-muted: var(--muted, #648095);
  --ka-pale: var(--pale, #edf6fb);
  --ka-good: #1d7a61;
  --ka-bad: #b04554;
  --ka-warn: #8a5b17;
  color: var(--ka-ink);
}
.ka-hero *,
.ka-home *,
.ka-progress *,
.ka-lessons *,
.ka-quiz *,
.ka-demo *,
.ka-cta * { box-sizing: border-box; }
.ka-hero h1, .ka-hero h2, .ka-hero h3,
.ka-home h2,
.ka-lessons h1, .ka-lessons h2, .ka-lessons h3,
.ka-quiz h2, .ka-quiz h3,
.ka-demo h2, .ka-demo h3,
.ka-cta h2 { font-family: "Songti SC", "SimSun", serif; }

.ka-hero { display: grid; grid-template-columns: minmax(0, 1.25fr) minmax(300px, .75fr); gap: 58px; align-items: center; padding-top: 58px; padding-bottom: 40px; }
.ka-breadcrumb { display: flex; gap: 8px; color: var(--ka-muted); font-size: 12px; margin-bottom: 18px; }
.ka-breadcrumb a:hover { color: var(--ka-accent); }
.ka-hero h1 { font-size: clamp(44px, 5.6vw, 68px); line-height: 1.08; letter-spacing: -2px; font-weight: 700; }
.ka-lead { margin-top: 20px; color: #3d5f75; font-size: 16px; line-height: 1.85; max-width: 650px; }
.ka-hero-actions { display: flex; gap: 18px; align-items: center; flex-wrap: wrap; margin-top: 26px; }
.ka-hero-actions .button { min-height: 48px; }
.ka-note { margin-top: 18px; color: var(--ka-muted); font-size: 11.5px; line-height: 1.65; max-width: 620px; }
.ka-hero-card { background: #fff; border: 1px solid var(--ka-line); border-radius: 4px; padding: 20px 22px; box-shadow: 0 18px 45px #17384f0c; }
.ka-card-head { display: flex; justify-content: space-between; align-items: baseline; padding-bottom: 12px; border-bottom: 1px solid #edf3f7; font-size: 12px; color: var(--ka-muted); }
.ka-card-head b { color: var(--ka-accent); font-size: 12px; }
.ka-path { list-style: none; padding: 0; margin: 0; }
.ka-path li { display: flex; gap: 12px; align-items: flex-start; padding: 12px 0; border-bottom: 1px solid #f0f5f8; }
.ka-path li:last-child { border-bottom: 0; }
.ka-path > li > b { font-family: Georgia, serif; color: #b9cad4; font-size: 15px; line-height: 1.2; min-width: 22px; }
.ka-path strong { display: block; font-size: 14px; font-weight: 700; }
.ka-path small { display: block; color: var(--ka-muted); font-size: 11px; line-height: 1.45; margin-top: 2px; }
.ka-card-foot { display: flex; justify-content: space-between; gap: 10px; border-top: 1px solid #edf3f7; padding-top: 12px; font-size: 11px; color: var(--ka-muted); }
.ka-card-foot a { color: var(--ka-accent); }

.ka-progress { margin-top: 8px; margin-bottom: 46px; background: #fff; border: 1px solid var(--ka-line); border-radius: 4px; padding: 16px 18px; }
.ka-progress-head { display: flex; justify-content: space-between; align-items: center; gap: 14px; margin-bottom: 10px; }
.ka-progress-head > div { display: flex; align-items: baseline; gap: 14px; flex-wrap: wrap; }
.ka-progress-head b { font-size: 13px; }
.ka-progress-head span { color: var(--ka-muted); font-size: 11px; }
.ka-bar { height: 8px; background: #eaf2f7; border-radius: 99px; overflow: hidden; }
.ka-bar i { display: block; height: 100%; width: 0; background: linear-gradient(90deg, #3485b7, #5ea9d2); border-radius: 99px; transition: width .25s ease; }
.ka-chips { display: flex; gap: 7px; flex-wrap: wrap; margin-top: 12px; }
.ka-chips button { border: 1px solid var(--ka-line); background: #fff; color: #3d5f75; border-radius: 99px; padding: 5px 10px; font-size: 10.5px; cursor: pointer; }
.ka-chips button:hover { border-color: #9dc4d9; }
.ka-chips button[aria-current="true"] { border-color: var(--ka-accent); color: var(--ka-accent); background: var(--ka-pale); }
.ka-chips button.done::after { content: " ✓"; color: var(--ka-good); }

.ka-lesson-layout { display: grid; grid-template-columns: 280px minmax(0, 1fr); gap: 34px; align-items: start; }
.ka-lesson-nav { position: sticky; top: 102px; }
.ka-lesson-nav-head h2 { font-size: 28px; margin-top: 2px; }
.ka-lesson-nav ol { list-style: none; padding: 0; margin: 18px 0 0; counter-reset: lesson; }
.ka-lesson-nav li { counter-increment: lesson; }
.ka-lesson-nav button { width: 100%; display: grid; grid-template-columns: 26px 1fr; gap: 8px; align-items: start; text-align: left; border: 0; border-top: 1px solid #e7eff4; background: transparent; padding: 11px 0; color: #3d5f75; font-size: 12px; line-height: 1.45; cursor: pointer; }
.ka-lesson-nav button::before { content: counter(lesson, decimal-leading-zero); font-family: Georgia, serif; color: #b9cad4; font-size: 12px; }
.ka-lesson-nav button:hover { color: var(--ka-accent); }
.ka-lesson-nav button[aria-current="true"] { color: var(--ka-accent); font-weight: 700; }
.ka-lesson-nav button[aria-current="true"]::before { color: var(--ka-accent); }
.ka-lesson-nav button.done::after { content: "✓"; color: var(--ka-good); justify-self: end; }
.ka-lesson-nav-note { color: var(--ka-muted); font-size: 10.5px; line-height: 1.55; margin-top: 18px; }

.ka-lesson { background: #fff; border: 1px solid var(--ka-line); border-radius: 4px; padding: 30px 32px 32px; min-width: 0; }
.ka-lesson-head { display: flex; justify-content: space-between; gap: 20px; align-items: flex-start; padding-bottom: 16px; border-bottom: 1px solid #edf3f7; }
.ka-lesson-head .ka-eyebrow { color: var(--ka-accent); font-size: 10px; letter-spacing: .14em; text-transform: uppercase; font-weight: 700; }
.ka-lesson-head h2 { font-size: 34px; line-height: 1.18; letter-spacing: -.6px; margin-top: 6px; }
.ka-lesson-head .ka-goal { color: var(--ka-muted); font-size: 12px; line-height: 1.65; margin-top: 8px; max-width: 680px; }
.ka-lesson-meta { flex-shrink: 0; color: var(--ka-muted); font-size: 10.5px; text-align: right; line-height: 1.6; }
.ka-lesson-meta b { display: block; color: var(--ka-ink); font-size: 20px; font-family: Georgia, serif; font-weight: 400; }
.ka-lesson-body { padding-top: 20px; }
.ka-visual { border: 1px solid #e3edf3; border-radius: 4px; background: #fbfdfe; padding: 14px; margin-bottom: 20px; overflow: hidden; }
.ka-visual svg { display: block; width: 100%; height: auto; max-width: 100%; }
.ka-visual-head { display: flex; justify-content: space-between; align-items: center; gap: 12px; margin-bottom: 10px; flex-wrap: wrap; }
.ka-visual-head span { color: var(--ka-muted); font-size: 10.5px; }
.ka-scenario { border: 1px solid #e3edf3; border-radius: 3px; background: #fff; padding: 8px; cursor: pointer; }
.ka-scenario:hover, .ka-scenario:focus-visible { border-color: #9dc4d9; outline: 2px solid #3485b755; outline-offset: 1px; }
.ka-controls { display: flex; gap: 9px; flex-wrap: wrap; margin-top: 10px; }
.ka-controls label { display: flex; align-items: center; gap: 7px; font-size: 10.5px; color: var(--ka-muted); }
.ka-controls input[type="range"] { width: 100px; }
.ka-toggle { display: inline-flex; border: 1px solid var(--ka-line); border-radius: 3px; overflow: hidden; }
.ka-toggle button { border: 0; background: #fff; color: #4c6b80; padding: 6px 10px; font-size: 10.5px; cursor: pointer; }
.ka-toggle button[aria-pressed="true"] { background: var(--ka-accent); color: #fff; }
.ka-points { list-style: none; padding: 0; margin: 0; display: grid; gap: 8px; }
.ka-points li { position: relative; padding-left: 18px; color: #31536a; font-size: 13px; line-height: 1.7; }
.ka-points li::before { content: ""; position: absolute; left: 2px; top: .65em; width: 5px; height: 5px; border-radius: 50%; background: var(--ka-accent); }
.ka-mistake { margin-top: 18px; border-left: 3px solid #d4a95f; background: #fffaf0; padding: 11px 14px; border-radius: 0 4px 4px 0; }
.ka-mistake b { display: block; color: var(--ka-warn); font-size: 11px; margin-bottom: 3px; }
.ka-mistake p { color: #6b562d; font-size: 11.5px; line-height: 1.6; }
.ka-exercise { margin-top: 20px; border: 1px solid #dce9f1; border-radius: 4px; background: #f8fbfd; padding: 15px 16px; }
.ka-exercise-head { display: flex; justify-content: space-between; gap: 12px; align-items: baseline; margin-bottom: 8px; }
.ka-exercise-head b { font-size: 12px; color: var(--ka-accent); }
.ka-exercise p { color: #31536a; font-size: 12px; line-height: 1.65; }
.ka-hint { color: var(--ka-muted) !important; font-size: 10.5px !important; margin-top: 7px; }
.ka-feedback { margin-top: 10px; border-radius: 3px; padding: 9px 11px; font-size: 11px; line-height: 1.6; }
.ka-feedback.good { background: #eef8f4; border: 1px solid #cfe8de; color: #1d6b55; }
.ka-feedback.bad { background: #fff4f5; border: 1px solid #f0d2d6; color: #8c2632; }
.ka-feedback.info { background: #f2f8fc; border: 1px solid #d8e8f2; color: #31536a; }
.ka-lesson-foot { display: flex; justify-content: space-between; gap: 10px; align-items: center; flex-wrap: wrap; margin-top: 22px; padding-top: 16px; border-top: 1px solid #edf3f7; }
.ka-lesson-foot > div { display: flex; gap: 8px; flex-wrap: wrap; }
.ka-button { display: inline-flex; align-items: center; justify-content: center; gap: 6px; min-height: 38px; padding: 7px 13px; border: 1px solid var(--ka-line); border-radius: 3px; background: #fff; color: #31536a; font-size: 11.5px; line-height: 1.3; cursor: pointer; }
.ka-button:hover:not(:disabled) { border-color: #9dc4d9; background: #f5fafd; }
.ka-button.primary { background: var(--ka-accent); border-color: var(--ka-accent); color: #fff; font-weight: 700; }
.ka-button.primary:hover:not(:disabled) { background: #2a739f; }
.ka-button:disabled { opacity: .5; cursor: default; }
.ka-text-button { border: 0; background: transparent; color: var(--ka-accent); font-size: 10.5px; padding: 4px 0; cursor: pointer; text-decoration: underline; text-underline-offset: 3px; }
.ka-text-button:hover { color: #225f84; }

.ka-section-head { max-width: 760px; margin-bottom: 22px; }
.ka-section-head .section-kicker { margin-bottom: 7px; }
.ka-section-head h2 { font-size: clamp(30px, 3.6vw, 42px); line-height: 1.18; letter-spacing: -1px; }
.ka-section-head > p:last-child { color: var(--ka-muted); font-size: 12.5px; line-height: 1.7; margin-top: 9px; }
.ka-quiz { margin-top: 68px; padding-top: 46px; border-top: 1px solid var(--ka-line); }
.ka-q { background: #fff; border: 1px solid var(--ka-line); border-radius: 4px; padding: 18px 20px; margin-bottom: 12px; }
.ka-q legend { font-size: 13px; font-weight: 700; line-height: 1.5; padding: 0; margin-bottom: 10px; }
.ka-q fieldset { border: 0; padding: 0; margin: 0; }
.ka-options { display: grid; gap: 6px; }
.ka-option { display: flex; gap: 9px; align-items: flex-start; border: 1px solid #e4edf3; border-radius: 3px; padding: 8px 10px; font-size: 11.5px; line-height: 1.5; cursor: pointer; }
.ka-option input[type="radio"] { display: inline-block; width: 16px; height: 16px; min-width: 16px; padding: 0; margin: 3px 0 0; flex: 0 0 16px; accent-color: var(--ka-accent); }
.ka-option:hover { border-color: #b9d5e4; background: #fbfdfe; }
.ka-option input { margin-top: 3px; accent-color: var(--ka-accent); }
.ka-option.correct { border-color: #b7ddcf; background: #f0faf6; }
.ka-option.wrong { border-color: #ecc9ce; background: #fff5f6; }
.ka-q-actions { display: flex; gap: 10px; align-items: center; margin-top: 10px; flex-wrap: wrap; }
.ka-q-feedback { margin-top: 10px; border-top: 1px dashed #dce8ef; padding-top: 9px; font-size: 11px; line-height: 1.6; color: #31536a; }
.ka-q-feedback b { color: var(--ka-ink); }
.ka-q-feedback ul { list-style: none; padding: 0; margin: 7px 0 0; display: grid; gap: 4px; }
.ka-q-feedback li { color: var(--ka-muted); }
.ka-q-feedback li.ok { color: var(--ka-good); }
.ka-quiz-result { margin-top: 14px; padding: 13px 15px; border-radius: 4px; background: var(--ka-pale); border: 1px solid #d5e8f1; color: #31536a; font-size: 12px; line-height: 1.6; }
.ka-quiz-result b { font-size: 15px; color: var(--ka-accent); }

.ka-demo { margin-top: 68px; padding-top: 46px; border-top: 1px solid var(--ka-line); }
.ka-demo-grid { display: grid; grid-template-columns: minmax(0, 1.15fr) minmax(300px, .85fr); gap: 26px; align-items: start; }
.ka-demo-chart { background: #fff; border: 1px solid var(--ka-line); border-radius: 4px; padding: 14px; }
.ka-demo-chart svg { display: block; width: 100%; height: auto; }
.ka-demo-panel { background: #fff; border: 1px solid var(--ka-line); border-radius: 4px; padding: 20px; }
.ka-demo-label { display: inline-block; background: #fff6e8; color: #8a5b17; border: 1px solid #efddc0; border-radius: 99px; padding: 3px 9px; font-size: 9.5px; margin-bottom: 12px; }
.ka-demo-step b { display: block; color: var(--ka-accent); font-size: 10.5px; margin-bottom: 4px; }
.ka-demo-step h3 { font-size: 22px; line-height: 1.25; margin-bottom: 7px; }
.ka-demo-step p { color: var(--ka-muted); font-size: 12px; line-height: 1.7; }
.ka-demo-actions { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; margin-top: 14px; padding-top: 12px; border-top: 1px solid #edf3f7; }
.ka-demo-ledger { margin-top: 12px; }
.ka-demo-ledger table { width: 100%; border-collapse: collapse; font-size: 10.5px; }
.ka-demo-ledger th, .ka-demo-ledger td { text-align: left; padding: 5px 6px; border-bottom: 1px solid #eef4f8; }
.ka-demo-ledger th { color: var(--ka-muted); font-weight: 600; }
.ka-demo-ledger .net { color: var(--ka-good); font-weight: 700; }

.ka-cta { margin-top: 68px; padding-top: 46px; padding-bottom: 52px; border-top: 1px solid var(--ka-line); }
.ka-cta-head { max-width: 720px; margin-bottom: 20px; }
.ka-cta-head h2 { font-size: clamp(30px, 3.6vw, 42px); line-height: 1.18; letter-spacing: -1px; }
.ka-cta-head p:last-child { color: var(--ka-muted); font-size: 12.5px; line-height: 1.7; margin-top: 9px; }
.ka-market-cards { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.ka-market-cards a { display: flex; flex-direction: column; gap: 5px; background: #fff; border: 1px solid var(--ka-line); border-radius: 4px; padding: 22px 24px; transition: border-color .15s, transform .15s; }
.ka-market-cards a:hover { border-color: #9dc4d9; transform: translateY(-2px); }
.ka-market-tag { color: var(--ka-accent); font-size: 10px; letter-spacing: .12em; text-transform: uppercase; font-weight: 700; }
.ka-market-cards b { font-family: "Songti SC", "SimSun", serif; font-size: 26px; line-height: 1.2; }
.ka-market-cards small { color: var(--ka-muted); font-size: 11px; }
.ka-market-cards strong { margin-top: 20px; font-size: 12px; color: var(--ka-accent); }
.ka-cta-note { margin-top: 14px; color: var(--ka-muted); font-size: 11px; }
.ka-cta-note a { color: var(--ka-accent); text-decoration: underline; text-underline-offset: 3px; }

/* Home entry band ---------------------------------------------------------- */
.ka-home {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(320px, .95fr);
  gap: 52px;
  align-items: center;
  padding-top: 66px;
  padding-bottom: 66px;
  border-top: 1px solid var(--ka-line);
}
.ka-home-copy h2 { font-size: clamp(34px, 4.2vw, 52px); line-height: 1.14; letter-spacing: -1.4px; }
.ka-home-copy > p { color: #3d5f75; font-size: 13.5px; line-height: 1.8; margin-top: 14px; max-width: 560px; }
.ka-home-actions { display: flex; gap: 16px; align-items: center; flex-wrap: wrap; margin-top: 22px; }
.ka-home-note { color: var(--ka-muted) !important; font-size: 10.5px !important; line-height: 1.6 !important; margin-top: 14px !important; }
.ka-home-steps { display: grid; gap: 0; border-top: 1px solid var(--ka-line); }
.ka-home-steps a { display: grid; grid-template-columns: 38px 1fr; grid-template-rows: auto auto; gap: 1px 10px; align-items: start; padding: 13px 0; border-bottom: 1px solid #e7eff4; transition: padding-left .15s, color .15s; }
.ka-home-steps a:hover { padding-left: 5px; color: var(--ka-accent); }
.ka-home-steps b { grid-row: 1 / span 2; font-family: Georgia, serif; color: #b9cad4; font-size: 14px; font-weight: 400; line-height: 1.3; }
.ka-home-steps span { grid-column: 2; display: block; font-size: 13px; font-weight: 700; }
.ka-home-steps small { grid-column: 2; display: block; color: var(--ka-muted); font-size: 10.5px; line-height: 1.45; margin-top: 1px; }
.ka-home-steps a:hover b { color: var(--ka-accent); }
.kline-nav small { color: var(--ka-muted, #648095); font-size: 10px; margin-left: 3px; }
@media (max-width: 1100px) {
  .kline-nav small { display: none; }
  .ka-hero { gap: 36px; }
  .ka-lesson-layout { grid-template-columns: 235px minmax(0, 1fr); gap: 26px; }
  .ka-lesson { padding: 26px; }
  .ka-lesson-head h2 { font-size: 30px; }
}
@media (max-width: 920px) { .ka-home { grid-template-columns: 1fr; gap: 28px; padding-top: 44px; padding-bottom: 44px; } }
@media (max-width: 640px) {
  .ka-home-copy h2 { font-size: 34px; }
  .ka-home-actions { flex-direction: column; align-items: stretch; }
  .ka-home-actions .button, .ka-home-actions .text-link { text-align: center; }
}

@media (max-width: 920px) {
  .ka-hero { grid-template-columns: 1fr; gap: 28px; padding-top: 40px; }
  .ka-hero-card { max-width: 560px; }
  .ka-lesson-layout { grid-template-columns: 1fr; }
  .ka-lesson-nav { position: static; }
  .ka-lesson-nav ol { display: grid; grid-template-columns: 1fr 1fr; gap: 0 18px; }
  .ka-lesson-nav-note { display: none; }
  .ka-demo-grid { grid-template-columns: 1fr; }
  .ka-market-cards { grid-template-columns: 1fr; }
}
@media (max-width: 640px) {
  .ka-hero h1 { font-size: 45px; letter-spacing: -1.5px; }
  .ka-lead { font-size: 14.5px; }
  .ka-hero-actions { flex-direction: column; align-items: stretch; }
  .ka-hero-actions .button, .ka-hero-actions .text-link { justify-content: center; text-align: center; }
  .ka-progress-head { align-items: flex-start; flex-direction: column; gap: 8px; }
  .ka-lesson { padding: 20px 17px 22px; }
  .ka-lesson-head { flex-direction: column; gap: 8px; }
  .ka-lesson-head h2 { font-size: 25px; }
  .ka-lesson-meta { text-align: left; }
  .ka-lesson-nav ol { grid-template-columns: 1fr; }
  .ka-lesson-foot { flex-direction: column; align-items: stretch; }
  .ka-lesson-foot > div { display: grid; grid-template-columns: 1fr 1fr; }
  .ka-section-head h2, .ka-cta-head h2 { font-size: 29px; }
  .ka-q { padding: 15px 13px; }
  .ka-option { font-size: 12px; }
  .ka-demo-panel { padding: 15px; }
  .ka-demo-step h3 { font-size: 19px; }
  .ka-demo-actions { display: grid; grid-template-columns: 1fr 1fr; }
  .ka-demo-actions .ka-text-button { grid-column: 1/-1; justify-self: start; }
  .ka-market-cards a { padding: 18px; }
  .ka-market-cards b { font-size: 23px; }
  .ka-chips { max-height: 104px; overflow-y: auto; }
}
@media (max-width: 390px) {
  .ka-hero h1 { font-size: 39px; }
  .ka-hero { padding-top: 30px; }
  .ka-progress { padding: 13px; }
  .ka-visual { padding: 9px; }
  .ka-controls { display: grid; grid-template-columns: 1fr; }
  .ka-controls input[type="range"] { width: 100%; }
  .ka-lesson-foot > div { grid-template-columns: 1fr; }
  .ka-demo-actions { grid-template-columns: 1fr; }
  .ka-demo-actions .ka-text-button { grid-column: auto; }
}
@media (prefers-reduced-motion: reduce) {
  * { scroll-behavior: auto !important; transition: none !important; }
}