:root {
  --options-navy: #10263f;
  --options-ink: #17313a;
  --options-orange: #d96a3b;
  --options-gold: #e2a63e;
  --options-blue: #2d6581;
  --options-paper: #fffaf0;
  --options-line: #ddcfbb;
  --options-muted: #62706e;
  --options-soft-blue: #eaf2f5;
  --options-soft-orange: #fff0e9;
  --options-danger: #a74235;
}

.page-options main {
  max-width: 1500px;
  padding-top: 24px;
}

.options-shell {
  max-width: 1180px;
  margin: 0 auto;
  color: var(--options-ink);
}

.options-shell *,
.options-shell *::before,
.options-shell *::after { box-sizing: border-box; }

.options-shell a { color: inherit; }
.options-shell p { color: var(--options-muted); line-height: 1.85; }
.options-shell h1,
.options-shell h2,
.options-shell h3 { font-family: "STSong", "Songti SC", "Noto Serif CJK SC", serif; }
.options-shell h2 { margin: 10px 0 16px; font-size: clamp(28px, 4vw, 44px); line-height: 1.25; letter-spacing: -.025em; }

.options-eyebrow,
.option-step,
.options-section-heading > span {
  display: block;
  color: var(--options-orange);
  font-size: 11px;
  font-weight: 900;
  letter-spacing: .16em;
  text-transform: uppercase;
}

.options-hero,
.option-article-hero {
  position: relative;
  overflow: hidden;
  display: grid;
  grid-template-columns: minmax(0, 1.55fr) minmax(250px, .65fr);
  gap: clamp(30px, 6vw, 80px);
  align-items: end;
  padding: clamp(42px, 7vw, 88px);
  color: #f7f2e8;
  background: radial-gradient(circle at 88% 2%, rgba(226, 166, 62, .2), transparent 29%), linear-gradient(145deg, #10263f, #183954 62%, #23566a);
  border-radius: 30px;
  box-shadow: 0 24px 60px rgba(43, 45, 42, .15);
}

.options-hero::after,
.option-article-hero::after {
  content: "";
  position: absolute;
  width: 340px;
  height: 340px;
  right: -130px;
  top: -160px;
  border: 56px solid rgba(255,255,255,.035);
  border-radius: 50%;
}

.options-hero > *,
.option-article-hero > * { position: relative; z-index: 1; }

.options-hero h1,
.option-article-hero h1 {
  margin: 18px 0 22px;
  font-size: clamp(40px, 5.4vw, 70px);
  line-height: 1.13;
  letter-spacing: -.045em;
}

.options-hero p,
.option-article-hero p { max-width: 700px; color: #cbd9de; font-size: 17px; }

.options-hero aside,
.option-article-hero aside {
  padding: 25px;
  border: 1px solid rgba(255,255,255,.18);
  border-radius: 18px;
  background: rgba(255,255,255,.07);
  backdrop-filter: blur(8px);
}

.options-hero aside small,
.option-article-hero aside span { display: block; color: #e8bc6f; font-weight: 800; letter-spacing: .1em; }
.options-hero aside ol { margin: 18px 0 0; padding: 0; list-style: none; }
.options-hero aside li { padding: 12px 0; border-top: 1px solid rgba(255,255,255,.14); }
.options-hero aside li b { display: inline-block; width: 38px; color: #e8bc6f; }
.option-article-hero aside b { display: block; margin-top: 15px; color: #fff; font: 700 25px/1.3 "STSong", "Songti SC", serif; }
.option-article-hero aside p { margin-bottom: 0; font-size: 14px; }

.options-hero-actions { display: flex; gap: 20px; align-items: center; flex-wrap: wrap; margin-top: 30px; }
.options-hero-actions a { display: inline-flex; min-height: 46px; align-items: center; padding: 0 24px; color: #fff; background: var(--options-orange); border-radius: 999px; text-decoration: none; font-weight: 800; }
.options-hero-actions span { color: #aebfc6; font-size: 13px; }

.options-principles { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; margin: 18px 0 70px; }
.options-principles article { padding: 26px; background: rgba(255,250,240,.72); border: 1px solid var(--options-line); border-radius: 16px; }
.options-principles span { color: #b6a58b; font: 700 28px/1 Georgia, serif; }
.options-principles b { display: block; margin: 16px 0 5px; font-size: 18px; }
.options-principles p { margin: 0; font-size: 14px; }

.option-guide-list { margin: 0 0 80px; }
.options-section-heading { margin-bottom: 25px; }
.options-section-heading p { max-width: 760px; margin: -5px 0 0; }
.option-guide-card { display: grid; grid-template-columns: 88px 1fr; gap: 26px; align-items: start; margin-top: 14px; padding: clamp(25px, 4vw, 42px); text-decoration: none; background: rgba(255,250,240,.78); border: 1px solid var(--options-line); border-radius: 20px; transition: transform .2s, box-shadow .2s, border-color .2s; }
.option-guide-card:hover { transform: translateY(-3px); border-color: #c4a981; box-shadow: 0 16px 36px rgba(65,52,35,.1); }
.option-guide-number { color: #baa98f; font: 700 38px/1 Georgia, serif; }
.option-guide-card small { color: var(--options-orange); font-weight: 900; letter-spacing: .13em; }
.option-guide-card h2 { margin: 9px 0; font-size: clamp(26px, 3vw, 38px); }
.option-guide-card p { max-width: 780px; margin: 0 0 17px; }
.option-guide-card b { color: var(--options-blue); font-size: 14px; }
.option-guide-card i { font-style: normal; transition: margin .2s; }
.option-guide-card:hover i { margin-left: 5px; }

.options-roadmap { display: grid; grid-template-columns: .9fr 1.1fr; gap: clamp(35px, 7vw, 90px); padding: clamp(35px, 6vw, 70px); color: #f6f1e7; background: #18343f; border-radius: 26px; }
.options-roadmap h2 { color: #fff; }
.options-roadmap p { color: #bdceca; }
.options-roadmap ol { margin: 0; padding: 0; list-style: none; }
.options-roadmap li { display: grid; grid-template-columns: 42px 1fr; gap: 14px; padding: 14px 0; border-top: 1px solid rgba(255,255,255,.13); }
.options-roadmap li > span { color: #dfb26b; font: 700 19px/1 Georgia, serif; }
.options-roadmap li b,
.options-roadmap li small { display: block; }
.options-roadmap li small { margin-top: 4px; color: #a9bbb7; }

.options-risk-note { display: flex; gap: 28px; margin: 18px 0 60px; padding: 24px 28px; background: #fff1e9; border-left: 4px solid var(--options-orange); border-radius: 10px; }
.options-risk-note b { flex: 0 0 auto; color: var(--options-danger); }
.options-risk-note p { margin: 0; }

.option-breadcrumb { display: flex; gap: 10px; margin: 4px 0 22px; color: #69736e; font-size: 14px; }
.option-breadcrumb a { font-weight: 800; text-decoration: none; }
.option-article-hero { align-items: center; }
.option-article-hero dl { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1px; margin: 30px 0 0; background: rgba(255,255,255,.15); border: 1px solid rgba(255,255,255,.15); border-radius: 13px; overflow: hidden; }
.option-article-hero dl div { padding: 15px; background: rgba(11,29,45,.72); }
.option-article-hero dt { color: #95acb6; font-size: 11px; }
.option-article-hero dd { margin: 5px 0 0; color: #fff; font-weight: 800; }

.option-toc { position: sticky; z-index: 5; top: 12px; display: flex; gap: 4px; justify-content: center; flex-wrap: wrap; width: max-content; max-width: calc(100% - 24px); margin: 18px auto 70px; padding: 7px; background: rgba(255,250,240,.9); border: 1px solid var(--options-line); border-radius: 999px; box-shadow: 0 10px 28px rgba(60,50,38,.08); backdrop-filter: blur(12px); }
.option-toc a { padding: 9px 14px; color: #53605d; text-decoration: none; font-size: 13px; font-weight: 800; border-radius: 999px; }
.option-toc a:hover { color: #fff; background: var(--options-navy); }

.option-section { margin: 0 0 26px; padding: clamp(32px, 5vw, 62px); background: rgba(255,250,240,.8); border: 1px solid var(--options-line); border-radius: 24px; scroll-margin-top: 90px; }
.split-section { display: grid; grid-template-columns: 1.05fr .95fr; gap: clamp(35px, 7vw, 84px); }
.split-section blockquote { margin: 28px 0 0; padding: 20px 24px; color: #6b503d; background: #f7e8d2; border-left: 4px solid var(--options-gold); }
.definition-stack { display: grid; gap: 12px; }
.definition-stack article { padding: 20px 22px; background: #f0eee7; border-radius: 13px; }
.definition-stack b { color: var(--options-navy); }
.definition-stack p { margin: 5px 0 0; font-size: 14px; }

.formula-band { margin: 26px 0; padding: clamp(24px, 4vw, 38px); color: #fff; background: var(--options-navy); border-radius: 18px; }
.formula-band small { display: block; color: #a9bec8; }
.formula-band strong { display: block; margin: 13px 0; color: #fff; font: 700 clamp(25px, 4vw, 42px)/1.25 Georgia, "STSong", serif; letter-spacing: -.02em; }
.formula-band p { margin: 0; color: #bdcdd4; }
.two-column-notes,
.comparison-grid,
.vega-directions,
.management-columns { display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px; }
.two-column-notes article,
.comparison-grid article,
.vega-directions article,
.management-columns article { padding: 25px; background: #f3eee4; border-radius: 15px; }
.two-column-notes h3,
.comparison-grid h3,
.management-columns h3 { margin: 0 0 8px; font-size: 22px; }
.two-column-notes p,
.comparison-grid p,
.vega-directions p,
.management-columns p { margin: 0; }
.worked-line { margin-top: 14px; padding: 24px 28px; border: 1px solid #e2b86e; border-radius: 15px; background: #fff6df; }
.worked-line span,
.worked-line b,
.worked-line small { display: block; }
.worked-line b { margin: 8px 0; color: var(--options-orange); font-size: clamp(18px, 3vw, 27px); }
.worked-line small { color: #766b58; }

.option-calculator,
.strategy-lab { background: #eef2f1; border-color: #cad6d2; }
.calculator-layout { display: grid; grid-template-columns: minmax(260px,.75fr) minmax(0,1.25fr); gap: 20px; }
.calculator-layout fieldset { display: grid; gap: 15px; margin: 0; padding: 25px; border: 1px solid #c5d1cd; border-radius: 15px; background: #fff; }
.calculator-layout legend { padding: 0 8px; font-weight: 800; }
.options-shell label { display: grid; gap: 7px; color: #4e5d59; font-size: 13px; font-weight: 800; }
.options-shell input,
.options-shell select { width: 100%; min-height: 44px; padding: 8px 11px; color: var(--options-ink); background: #fff; border: 1px solid #b7c5c1; border-radius: 8px; font: inherit; }
.options-shell input:focus,
.options-shell select:focus { outline: 3px solid rgba(45,101,129,.18); border-color: var(--options-blue); }
.calculator-output { display: grid; grid-template-columns: repeat(2,1fr); gap: 10px; }
.calculator-output article { padding: 21px; background: #fff; border-radius: 13px; }
.calculator-output article.primary { grid-column: 1 / -1; color: #fff; background: var(--options-blue); }
.calculator-output span,
.calculator-output strong { display: block; }
.calculator-output span { color: #76817e; font-size: 12px; }
.calculator-output article.primary span { color: #c6dbe4; }
.calculator-output strong { margin-top: 8px; font-size: clamp(20px,3vw,30px); }
.calculator-output > small { grid-column: 1 / -1; color: #697673; line-height: 1.6; }

.comparison-grid small { color: var(--options-orange); font-weight: 900; letter-spacing: .1em; }
.comparison-grid b { display: block; margin-top: 18px; color: var(--options-blue); }
.vega-equation { margin: 25px 0 14px; padding: 30px; text-align: center; color: #fff; background: linear-gradient(135deg, var(--options-blue), #174359); border-radius: 17px; }
.vega-equation strong,
.vega-equation span { display: block; }
.vega-equation strong { font: 700 clamp(22px,3vw,36px)/1.25 Georgia, serif; }
.vega-equation span { margin-top: 9px; color: #c7dce4; }
.vega-lead { max-width: 900px; font-size: 17px; line-height: 1.8; }
.vega-example { display: grid; grid-template-columns: 1.25fr .75fr; gap: 18px 28px; align-items: center; margin: 18px 0; padding: 25px 28px; border: 1px solid #e2b86e; border-radius: 15px; background: #fff6df; }
.vega-example small { color: var(--options-orange); font-weight: 900; letter-spacing: .1em; }
.vega-example h3 { margin: 7px 0; font-size: 22px; }
.vega-example p { margin: 0; }
.vega-example > strong { color: var(--options-orange); font: 700 clamp(23px,3vw,32px)/1.25 Georgia, serif; }
.vega-example > p { grid-column: 1 / -1; color: #645b4d; }
.vega-directions article { position: relative; overflow: hidden; }
.vega-directions article::before { position: absolute; inset: 0 auto 0 0; width: 5px; content: ""; background: var(--options-blue); }
.vega-directions article.vega-short::before { background: var(--options-orange); }
.vega-directions small { color: var(--options-muted); font-weight: 900; letter-spacing: .08em; }
.vega-directions b { display: block; margin: 5px 0 14px; font-size: 21px; }
.vega-directions p { display: grid; grid-template-columns: 138px 1fr; gap: 10px; padding: 11px 0; border-top: 1px solid rgba(11,42,55,.1); }
.vega-directions em { color: var(--options-navy); font-style: normal; font-weight: 900; }
.vega-directions span { color: var(--options-muted); }
.vega-calculator { margin: 28px 0; padding: clamp(22px,4vw,34px); border-radius: 18px; color: #fff; background: var(--options-navy); }
.vega-calculator-copy small { color: #f3b45b; font-weight: 900; letter-spacing: .1em; }
.vega-calculator-copy h3 { margin: 7px 0; color: #fff; font-size: 25px; }
.vega-calculator-copy p { margin: 0; color: #bfd0d7; }
.vega-inputs { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; margin-top: 22px; }
.vega-inputs label { color: #cfdee4; font-size: 13px; font-weight: 800; }
.vega-inputs input { box-sizing: border-box; width: 100%; margin-top: 7px; padding: 12px 13px; border: 1px solid #58717c; border-radius: 8px; color: #fff; background: #163c4d; font: inherit; }
.vega-results { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; margin-top: 14px; }
.vega-results article { padding: 16px; border-radius: 11px; background: rgba(255,255,255,.08); }
.vega-results span, .vega-results strong { display: block; }
.vega-results span { color: #bcd0d8; font-size: 12px; }
.vega-results strong { margin-top: 7px; font-size: 18px; }
.vega-results .long-result { background: rgba(54,137,164,.3); }
.vega-results .short-result { background: rgba(217,106,59,.25); }
.iv-playbook { margin-top: 30px; }
.iv-playbook > h3 { font-size: 26px; }
.iv-playbook > div { display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px; }
.iv-playbook article { padding: 24px; border: 1px solid var(--options-line); border-radius: 14px; background: #fff; }
.iv-playbook span { color: var(--options-orange); font-size: 12px; font-weight: 900; letter-spacing: .08em; }
.iv-playbook b { display: block; margin: 7px 0; color: var(--options-navy); font-size: 20px; }
.iv-playbook p { margin: 0; color: var(--options-muted); }
.fine-print { margin: 18px 0 0; font-size: 13px; }

.correction-section ol,
.checklist-section ol { margin: 25px 0 0; padding: 0; list-style: none; }
.correction-section li { display: grid; grid-template-columns: minmax(190px,.6fr) 1.4fr; gap: 28px; padding: 20px 0; border-top: 1px solid var(--options-line); }
.correction-section li b { color: var(--options-navy); }
.correction-section li span { color: var(--options-muted); line-height: 1.7; }

.payoff-grid { display: grid; grid-template-columns: repeat(3,1fr); gap: 13px; margin: 25px 0 15px; }
.payoff-grid article { padding: 24px; background: #edf2f1; border-radius: 15px; }
.payoff-grid article.danger { background: var(--options-soft-orange); }
.payoff-grid small,
.payoff-grid b { display: block; }
.payoff-grid small { color: #77827f; }
.payoff-grid b { margin: 14px 0 8px; color: var(--options-navy); font-size: 20px; line-height: 1.4; }
.payoff-grid .danger b { color: var(--options-danger); }
.payoff-grid p { margin: 0; font-size: 14px; }
.formula-pair { display: grid; grid-template-columns: repeat(2,1fr); gap: 13px; }
.formula-pair div { padding: 21px; text-align: center; color: #fff; background: var(--options-navy); border-radius: 14px; }
.formula-pair span,
.formula-pair b { display: block; }
.formula-pair span { color: #9fb4be; font-size: 12px; }
.formula-pair b { margin-top: 8px; font-size: 18px; }
.option-warning { margin-top: 14px; padding: 20px 23px; color: #6d4d3b; background: #fff0e7; border-left: 4px solid var(--options-orange); border-radius: 10px; line-height: 1.7; }

.probability-table-wrap { overflow-x: auto; }
.probability-table-wrap table { width: 100%; min-width: 680px; border-collapse: collapse; }
.probability-table-wrap th,
.probability-table-wrap td { padding: 15px; text-align: left; border-bottom: 1px solid var(--options-line); }
.probability-table-wrap th { color: #fff; background: var(--options-navy); }
.probability-table-wrap tbody tr:nth-child(even) { background: #f4eee3; }

.lab-inputs { display: grid; grid-template-columns: repeat(4,1fr); gap: 13px; margin: 25px 0; }
.lab-results { display: grid; grid-template-columns: repeat(3,1fr); gap: 10px; }
.lab-results article { padding: 20px; background: #fff; border-radius: 13px; }
.lab-results article.primary { color: #fff; background: var(--options-blue); }
.lab-results span,
.lab-results strong,
.lab-results small { display: block; }
.lab-results span { color: #788582; font-size: 12px; }
.lab-results .primary span,
.lab-results .primary small { color: #c8dce4; }
.lab-results strong { margin: 9px 0 5px; font-size: 20px; }
.lab-results small { color: #7a8583; }
.payoff-chart { margin-top: 18px; padding: 24px; background: #fff; border-radius: 15px; }
.payoff-chart h3 { margin: 0; font-size: 23px; }
.payoff-chart p { margin: 4px 0 15px; font-size: 13px; }
.payoff-chart canvas { display: block; width: 100%; height: 330px; border-radius: 9px; }
.calc-error { color: var(--options-danger) !important; font-weight: 800; }

.greek-grid { display: grid; grid-template-columns: repeat(4,1fr); gap: 12px; margin: 24px 0; }
.greek-grid article { padding: 22px; background: #edf2f1; border-top: 4px solid var(--options-blue); border-radius: 13px; }
.greek-grid b { font-size: 19px; }
.greek-grid p { margin: 8px 0 0; font-size: 13px; }
.mini-formula { margin-top: 18px; padding: 14px; text-align: center; color: #fff; background: var(--options-blue); border-radius: 9px; font-weight: 800; }
.mini-formula.danger { background: var(--options-danger); }

.checklist-section li { display: grid; grid-template-columns: 52px 1fr; gap: 18px; padding: 20px 0; border-top: 1px solid var(--options-line); }
.checklist-section li > span { color: #b6a58b; font: 700 24px/1 Georgia, serif; }
.checklist-section li b { font-size: 18px; }
.checklist-section li p { margin: 5px 0 0; }

.option-sources { margin: 55px 0 25px; padding: 30px; background: #e8e2d6; border-radius: 18px; }
.option-sources h2 { font-size: 27px; }
.option-sources ul { display: flex; flex-wrap: wrap; gap: 10px 22px; margin: 15px 0 0; padding-left: 18px; }
.option-sources a { color: var(--options-blue); font-weight: 800; }
.option-next { display: flex; justify-content: space-between; gap: 20px; margin-bottom: 60px; }
.option-next a { font-weight: 800; text-decoration: none; }
.option-next a:last-child { color: var(--options-orange); }

/* Delta presentation — faithful web treatment of the 12-slide source deck. */
.delta-deck-page {
  --delta-navy: #141e3c;
  --delta-gold: #f0b429;
  --delta-paper: #f5f7fb;
  --delta-red: #d8584c;
  --delta-green: #2d9b72;
  max-width: 1240px;
}
.delta-toc {
  position: sticky;
  z-index: 20;
  top: 10px;
  display: flex;
  gap: 7px;
  overflow-x: auto;
  margin: 16px 0 24px;
  padding: 10px;
  border: 1px solid #dfe3eb;
  border-radius: 999px;
  background: rgba(245,247,251,.94);
  box-shadow: 0 10px 28px rgba(20,30,60,.08);
  scrollbar-width: none;
}
.delta-toc::-webkit-scrollbar { display: none; }
.delta-toc a {
  flex: 0 0 auto;
  padding: 8px 13px;
  border-radius: 999px;
  color: #4d566e;
  text-decoration: none;
  font-size: 12px;
  font-weight: 800;
}
.delta-toc a:hover { color: #fff; background: var(--delta-navy); }
.delta-slide {
  position: relative;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  min-height: 660px;
  margin: 0 0 28px;
  padding: clamp(34px,5vw,64px) clamp(28px,6vw,78px) 24px;
  color: var(--delta-navy);
  background: var(--delta-paper);
  border: 1px solid #e1e5ed;
  border-radius: 26px;
  box-shadow: 0 20px 50px rgba(20,30,60,.08);
  scroll-margin-top: 92px;
}
.delta-slide::before {
  position: absolute;
  top: 0;
  left: 0;
  width: 9px;
  height: 100%;
  content: "";
  background: var(--delta-gold);
}
.delta-slide > header {
  display: grid;
  grid-template-columns: 52px 1fr;
  gap: 18px;
  align-items: start;
  margin-bottom: 30px;
}
.delta-slide > header > span {
  color: var(--delta-gold);
  font: 700 26px/1 Georgia, serif;
}
.delta-slide h1,
.delta-slide h2,
.delta-slide h3 { font-family: Calibri, "Microsoft YaHei", sans-serif; }
.delta-slide > header h2 { margin: -5px 0 7px; color: var(--delta-navy); font-size: clamp(27px,3.4vw,43px); line-height: 1.18; }
.delta-slide > header p { margin: 0; color: #68718a; font-size: 17px; line-height: 1.55; }
.delta-slide footer {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  margin-top: auto;
  padding-top: 24px;
  color: #838a9c;
  font-size: 11px;
  letter-spacing: .02em;
}
.delta-slide footer b { color: var(--delta-gold); }
.delta-title-slide,
.delta-closing-slide {
  min-height: 690px;
  color: #fff;
  background: radial-gradient(circle at 87% 15%, rgba(240,180,41,.2), transparent 24%), linear-gradient(135deg, #141e3c, #1f2d55);
  border-color: #141e3c;
}
.delta-title-slide::after,
.delta-closing-slide::after {
  position: absolute;
  right: -100px;
  bottom: -180px;
  width: 430px;
  height: 430px;
  content: "";
  border: 72px solid rgba(255,255,255,.035);
  border-radius: 50%;
}
.delta-title-slide .delta-slide-body,
.delta-closing-slide .delta-slide-body { position: relative; z-index: 1; margin: auto 0; }
.delta-badge {
  display: inline-flex;
  padding: 8px 14px;
  color: var(--delta-gold);
  border: 1px solid rgba(240,180,41,.55);
  border-radius: 999px;
  font-size: 12px;
  font-weight: 800;
  letter-spacing: .08em;
}
.delta-title-slide h1 { max-width: 850px; margin: 28px 0 16px; color: #fff; font-size: clamp(44px,7vw,82px); line-height: 1.06; letter-spacing: -.045em; }
.delta-title-slide .delta-lead { max-width: 790px; margin: 0; color: #dce2ef; font-size: clamp(19px,2.6vw,29px); line-height: 1.5; }
.delta-title-slide .delta-note { margin: 34px 0 0; color: var(--delta-gold); font-size: 15px; font-weight: 800; }
.delta-title-slide footer,
.delta-closing-slide footer { position: relative; z-index: 1; color: #aab2c5; }
.delta-three-cards,
.delta-summary-steps { display: grid; grid-template-columns: repeat(3,1fr); gap: 16px; }
.delta-three-cards section,
.delta-summary-steps section { padding: 24px; background: #fff; border-top: 5px solid var(--delta-gold); border-radius: 14px; box-shadow: 0 10px 25px rgba(20,30,60,.06); }
.delta-three-cards i,
.delta-summary-steps i { color: #b5bac7; font: 700 24px/1 Georgia, serif; font-style: normal; }
.delta-three-cards h3,
.delta-summary-steps h3 { margin: 15px 0 7px; color: var(--delta-navy); font-size: 20px; }
.delta-three-cards p,
.delta-summary-steps p { margin: 0; color: #626b80; line-height: 1.7; }
.delta-slide blockquote {
  margin: 26px 0 15px;
  padding: 22px 26px;
  color: #fff;
  background: var(--delta-navy);
  border-left: 6px solid var(--delta-gold);
  border-radius: 8px;
  font-size: clamp(18px,2.2vw,25px);
  font-style: normal;
  font-weight: 800;
  line-height: 1.6;
}
.delta-callout,
.delta-highlight { margin: 0; color: #7a5a18 !important; font-weight: 800; }
.delta-definition { padding: 24px 28px; background: #fff; border-left: 6px solid var(--delta-gold); border-radius: 10px; }
.delta-definition span { display: block; color: var(--delta-gold); font-size: 12px; font-weight: 900; letter-spacing: .12em; }
.delta-definition strong { display: block; margin: 9px 0; font-size: clamp(21px,2.8vw,31px); }
.delta-definition p { margin: 0; }
.delta-range-card { margin: 18px 0; padding: 22px 28px; color: #fff; background: var(--delta-navy); border-radius: 14px; }
.delta-range-card small,
.delta-range-card strong,
.delta-range-card em { display: block; }
.delta-range-card strong { color: var(--delta-gold); font-size: 38px; }
.delta-range-line { display: flex; gap: 12px; align-items: center; margin-top: 13px; }
.delta-range-line i { flex: 1; height: 6px; background: linear-gradient(90deg,#9ca9c5,var(--delta-gold)); border-radius: 999px; }
.delta-range-card p { margin: 5px 0; color: #d7ddeb; }
.delta-range-card em { color: #9ca6bd; font-size: 12px; font-style: normal; }
.delta-analogy,
.delta-example { display: grid; grid-template-columns: 120px 1fr; gap: 20px; align-items: start; padding: 18px 22px; background: #fff8e8; border-radius: 10px; }
.delta-analogy b,
.delta-example b { color: #9a6b05; }
.delta-analogy p,
.delta-example p { margin: 0; line-height: 1.65; }
.delta-analogy p:only-child,
.delta-example p:only-child { grid-column: 1 / -1; }
.delta-subheading { margin: 2px 0 10px; color: var(--delta-navy); font-size: 16px; }
.delta-bias-copy { display: grid; gap: 8px; }
.delta-bias-copy p { margin: 0; padding: 11px 16px; background: #fff; border-radius: 8px; }
.delta-bias-copy b { color: var(--delta-navy); }
.delta-bias-bands { display: grid; grid-template-columns: repeat(3,1fr); gap: 8px; margin: 22px 0; }
.delta-bias-bands section { padding: 20px; text-align: center; color: #fff; background: #818ba3; }
.delta-bias-bands section:first-child { background: #9ba4b7; border-radius: 10px 0 0 10px; }
.delta-bias-bands section:last-child { background: var(--delta-red); border-radius: 0 10px 10px 0; }
.delta-bias-bands strong,
.delta-bias-bands span { display: block; }
.delta-bias-bands strong { font-size: 26px; }
.delta-bias-bands span { margin-top: 5px; font-size: 13px; }
.delta-symmetry { margin: -10px 0 18px !important; color: #747d91 !important; font-size: 13px; }
.delta-probability-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.delta-probability-grid section { padding: 24px; background: #fff; border-radius: 13px; }
.delta-probability-grid small { color: var(--delta-gold); font-weight: 900; letter-spacing: .1em; }
.delta-probability-grid h3 { margin: 8px 0; font-size: 23px; }
.delta-probability-grid p { margin: 0; }
.delta-probability-bar { margin: 20px 0; padding: 20px 24px; color: #fff; background: #183a39; border-radius: 12px; }
.delta-probability-bar span,
.delta-probability-bar strong { display: block; }
.delta-probability-bar strong { color: #78d3a9; font-size: 34px; }
.delta-probability-bar i { display: block; width: 75%; height: 7px; margin: 11px 0; background: #78d3a9; border-radius: 999px; }
.delta-probability-ends { display: flex; justify-content: space-between; width: 75%; color: #a9c9bd; font-size: 11px; }
.delta-probability-ends em { font-style: normal; }
.delta-probability-bar p { margin: 0; color: #d1e5dd; }
.delta-table-wrap { overflow-x: auto; border: 1px solid #dce0e8; border-radius: 12px; }
.delta-table-wrap table { width: 100%; min-width: 880px; border-collapse: collapse; }
.delta-table-wrap th,
.delta-table-wrap td { padding: 14px 16px; text-align: left; border-bottom: 1px solid #dfe3ea; }
.delta-table-wrap th { color: #fff; background: var(--delta-navy); }
.delta-table-wrap tr:nth-child(even) td { background: #fff; }
.delta-table-wrap td:nth-child(3) b { color: var(--delta-red); font-size: 18px; white-space: nowrap; }
.delta-abbreviations { font-size: 12px; }
.delta-strategy-layout { display: grid; grid-template-columns: .8fr 1.2fr; gap: 22px; }
.delta-structure-card { padding: 28px; color: #fff; background: var(--delta-navy); border-radius: 14px; }
.delta-structure-card small { color: var(--delta-gold); font-weight: 900; }
.delta-structure-card p { margin: 17px 0; color: #e1e5ef; font-size: 18px; }
.delta-structure-card strong { display: block; margin-top: 28px; color: var(--delta-gold); line-height: 1.55; }
.delta-strategy-layout h3 { margin: 0; font-size: 24px; }
.delta-strategy-layout ul,
.delta-two-strategies ul,
.delta-neutral-points { padding-left: 22px; color: #5d667b; line-height: 1.85; }
.delta-strategy-layout li::marker,
.delta-two-strategies li::marker,
.delta-neutral-points li::marker { color: var(--delta-gold); }
.delta-suitable,
.delta-common { margin: 22px 0 0; padding: 17px 21px; color: #5d667b !important; background: #fff8e8; border-left: 5px solid var(--delta-gold); border-radius: 8px; }
.delta-suitable b,
.delta-common b { color: var(--delta-navy); }
.delta-two-strategies { display: grid; grid-template-columns: repeat(2,1fr); gap: 18px; }
.delta-two-strategies section { padding: 28px; background: #fff; border-radius: 14px; }
.delta-two-strategies section > span { color: #858da1; font-size: 12px; font-weight: 900; letter-spacing: .07em; text-transform: uppercase; }
.delta-two-strategies h3 { margin: 7px 0; font-size: 23px; }
.delta-two-strategies strong { display: block; color: var(--delta-red); font-size: 30px; }
.delta-neutral-hero { display: flex; justify-content: space-between; gap: 20px; align-items: center; padding: 24px 28px; color: #fff; background: var(--delta-navy); border-radius: 14px; }
.delta-neutral-hero strong { color: var(--delta-gold); font-size: clamp(34px,5vw,58px); }
.delta-neutral-hero span { font-size: 18px; font-weight: 800; }
.delta-neutral-types { display: grid; grid-template-columns: repeat(2,1fr); gap: 14px; margin: 18px 0; }
.delta-neutral-types p { margin: 0; padding: 18px; background: #fff; border-radius: 10px; }
.delta-neutral-types b { color: var(--delta-navy); }
.delta-summary-steps section:nth-child(2) { border-top-color: var(--delta-green); }
.delta-summary-steps section:nth-child(3) { border-top-color: var(--delta-red); }
.delta-core-balance { margin-top: 22px; padding: 25px; color: #fff; background: var(--delta-navy); border-radius: 14px; }
.delta-core-balance h3 { margin: 0 0 13px; color: var(--delta-gold); font-size: 24px; }
.delta-core-balance > div { display: flex; justify-content: space-between; gap: 20px; padding: 10px 0; border-top: 1px solid rgba(255,255,255,.14); }
.delta-core-balance p { margin: 0; color: #e0e4ee; }
.delta-core-balance a { flex: 0 0 auto; color: var(--delta-gold); font-weight: 800; text-decoration: none; }
.delta-closing-slide h2 { margin: 0 0 30px; color: #fff; font-size: clamp(40px,6vw,68px); }
.delta-closing-slide ol { margin: 0; padding: 0; list-style: none; }
.delta-closing-slide li { display: grid; grid-template-columns: 56px 1fr; gap: 18px; padding: 17px 0; border-top: 1px solid rgba(255,255,255,.15); font-size: clamp(18px,2.4vw,26px); }
.delta-closing-slide li b { color: var(--delta-gold); }
.delta-closing-slide blockquote { margin-top: 28px; background: rgba(255,255,255,.08); }
.delta-closing-slide .delta-risk { color: #b9c0d0; font-size: 13px; }

/* Match guide 03 to guide 01's article system without changing deck content. */
.delta-deck-page {
  --delta-navy: var(--options-navy);
  --delta-gold: var(--options-gold);
  --delta-paper: var(--options-paper);
  --delta-red: var(--options-orange);
  --delta-green: var(--options-blue);
  max-width: 1180px;
}
.delta-deck-page .delta-toc {
  position: sticky;
  z-index: 5;
  top: 12px;
  justify-content: center;
  flex-wrap: wrap;
  width: max-content;
  max-width: calc(100% - 24px);
  margin: 18px auto 70px;
  padding: 7px;
  overflow: visible;
  background: rgba(255,250,240,.9);
  border: 1px solid var(--options-line);
  border-radius: 999px;
  box-shadow: 0 10px 28px rgba(60,50,38,.08);
}
.delta-deck-page .delta-toc a { padding: 9px 14px; color: #53605d; font-size: 13px; }
.delta-deck-page .delta-slide {
  display: block;
  min-height: 0;
  margin: 0 0 26px;
  padding: clamp(32px,5vw,62px);
  overflow: visible;
  color: var(--options-ink);
  background: rgba(255,250,240,.8);
  border: 1px solid var(--options-line);
  border-radius: 24px;
  box-shadow: none;
}
.delta-deck-page .delta-slide::before { display: none; }
.delta-deck-page .delta-slide > header {
  display: block;
  margin-bottom: 28px;
}
.delta-deck-page .delta-slide > header > span {
  display: block;
  color: var(--options-orange);
  font: 900 11px/1.3 system-ui, sans-serif;
  letter-spacing: .16em;
}
.delta-deck-page .delta-slide h1,
.delta-deck-page .delta-slide h2,
.delta-deck-page .delta-slide h3 { font-family: "STSong", "Songti SC", "Noto Serif CJK SC", serif; }
.delta-deck-page .delta-slide > header h2 {
  margin: 10px 0 12px;
  color: var(--options-ink);
  font-size: clamp(28px,4vw,44px);
  line-height: 1.25;
}
.delta-deck-page .delta-slide > header p { color: var(--options-muted); }
.delta-deck-page .delta-slide footer {
  margin-top: 30px;
  padding-top: 18px;
  color: #8a8f8b;
  border-top: 1px solid var(--options-line);
}
.delta-deck-page .delta-title-slide {
  display: grid;
  grid-template-columns: minmax(0,1.55fr) minmax(250px,.65fr);
  gap: clamp(30px,6vw,80px);
  align-items: center;
  padding: clamp(42px,7vw,88px);
  overflow: hidden;
  color: #f7f2e8;
  background: radial-gradient(circle at 88% 2%, rgba(226,166,62,.2), transparent 29%), linear-gradient(145deg,#10263f,#183954 62%,#23566a);
  border: 0;
  border-radius: 30px;
  box-shadow: 0 24px 60px rgba(43,45,42,.15);
}
.delta-deck-page .delta-title-slide::after {
  display: block;
  right: -130px;
  top: -160px;
  bottom: auto;
  width: 340px;
  height: 340px;
  border: 56px solid rgba(255,255,255,.035);
}
.delta-deck-page .delta-title-slide .delta-slide-body { margin: 0; }
.delta-deck-page .delta-badge {
  padding: 0;
  color: var(--options-orange);
  border: 0;
  border-radius: 0;
  font-size: 11px;
  font-weight: 900;
  letter-spacing: .16em;
}
.delta-deck-page .delta-title-slide h1 {
  max-width: 760px;
  margin: 18px 0 22px;
  color: #fff;
  font-size: clamp(40px,5.4vw,70px);
  line-height: 1.13;
}
.delta-deck-page .delta-title-slide .delta-lead { color: #cbd9de; font-size: 17px; }
.delta-deck-page .delta-title-slide .delta-note { margin-top: 24px; color: #e8bc6f; font-size: 13px; }
.delta-deck-page .delta-title-slide footer {
  display: block;
  margin: 0;
  padding: 25px;
  color: #cbd9de;
  background: rgba(255,255,255,.07);
  border: 1px solid rgba(255,255,255,.18);
  border-radius: 18px;
}
.delta-deck-page .delta-title-slide footer span { display: block; line-height: 1.75; }
.delta-deck-page .delta-slide blockquote {
  color: #6b503d;
  background: #f7e8d2;
  border-left: 4px solid var(--options-gold);
  border-radius: 0;
  font-size: 17px;
}
.delta-deck-page .delta-range-card,
.delta-deck-page .delta-structure-card,
.delta-deck-page .delta-neutral-hero,
.delta-deck-page .delta-core-balance { background: var(--options-navy); border-radius: 18px; }
.delta-deck-page .delta-definition,
.delta-deck-page .delta-three-cards section,
.delta-deck-page .delta-summary-steps section,
.delta-deck-page .delta-probability-grid section,
.delta-deck-page .delta-two-strategies section,
.delta-deck-page .delta-neutral-types p { border: 1px solid rgba(221,207,187,.72); box-shadow: none; }
.delta-deck-page .delta-closing-slide {
  color: var(--options-ink);
  background: rgba(255,250,240,.8);
  border: 1px solid var(--options-line);
}
.delta-deck-page .delta-closing-slide::after { display: none; }
.delta-deck-page .delta-closing-slide .delta-slide-body { margin: 0; }
.delta-deck-page .delta-closing-slide h2 { color: var(--options-ink); font-size: clamp(32px,4vw,48px); }
.delta-deck-page .delta-closing-slide li { color: var(--options-ink); border-top-color: var(--options-line); font-size: clamp(17px,2vw,22px); }
.delta-deck-page .delta-closing-slide blockquote { background: #f7e8d2; }
.delta-deck-page .delta-closing-slide .delta-risk { color: var(--options-muted); }
.delta-deck-page .delta-closing-slide footer { color: #8a8f8b; }

@media (max-width: 900px) {
  .options-hero,
  .option-article-hero,
  .options-roadmap,
  .split-section { grid-template-columns: 1fr; }
  .options-principles,
  .payoff-grid,
  .lab-results { grid-template-columns: 1fr; }
  .lab-inputs { grid-template-columns: repeat(2,1fr); }
  .greek-grid { grid-template-columns: repeat(2,1fr); }
  .option-toc { position: static; width: auto; border-radius: 18px; }
  .delta-three-cards,
  .delta-summary-steps,
  .delta-strategy-layout { grid-template-columns: 1fr; }
  .delta-deck-page .delta-title-slide { grid-template-columns: 1fr; }
  .delta-deck-page .delta-toc { position: static; width: auto; border-radius: 18px; }
}

@media (max-width: 620px) {
  .page-options main { padding-left: 12px; padding-right: 12px; }
  .options-hero,
  .option-article-hero { padding: 34px 24px; border-radius: 22px; }
  .options-hero h1,
  .option-article-hero h1 { font-size: 38px; }
  .options-hero h1 br,
  .option-article-hero h1 br { display: none; }
  .options-principles { grid-template-columns: 1fr; }
  .option-guide-card { grid-template-columns: 48px 1fr; gap: 14px; padding: 24px 19px; }
  .option-guide-number { font-size: 28px; }
  .option-article-hero dl,
  .two-column-notes,
  .comparison-grid,
  .vega-directions,
  .iv-playbook > div,
  .management-columns,
  .formula-pair,
  .calculator-layout,
  .calculator-output,
  .lab-inputs,
  .greek-grid { grid-template-columns: 1fr; }
  .vega-example,
  .vega-inputs,
  .vega-results { grid-template-columns: 1fr; }
  .vega-example > p { grid-column: auto; }
  .vega-directions p { grid-template-columns: 1fr; gap: 3px; }
  .calculator-output article.primary { grid-column: auto; }
  .option-section { padding: 28px 20px; border-radius: 18px; }
  .formula-band strong { font-size: 24px; overflow-wrap: anywhere; }
  .correction-section li { grid-template-columns: 1fr; gap: 6px; }
  .payoff-chart { padding: 14px; }
  .payoff-chart canvas { height: 270px; }
  .options-risk-note,
  .option-next { display: block; }
  .options-risk-note p,
  .option-next a { display: block; margin-top: 10px; }
  .delta-toc { top: 6px; border-radius: 16px; }
  .delta-slide { min-height: 0; padding: 30px 21px 18px 28px; border-radius: 18px; }
  .delta-deck-page .delta-slide { padding: 28px 20px; border-radius: 18px; }
  .delta-deck-page .delta-title-slide { padding: 34px 24px; border-radius: 22px; }
  .delta-deck-page .delta-title-slide h1 { font-size: 38px; }
  .delta-title-slide,
  .delta-closing-slide { min-height: 0; }
  .delta-slide > header { display: block; }
  .delta-probability-grid,
  .delta-two-strategies,
  .delta-neutral-types { grid-template-columns: 1fr; }
  .delta-bias-bands { grid-template-columns: 1fr; }
  .delta-bias-bands section:first-child,
  .delta-bias-bands section:last-child { border-radius: 9px; }
  .delta-analogy,
  .delta-example { grid-template-columns: 1fr; gap: 5px; }
  .delta-neutral-hero,
  .delta-core-balance > div { display: block; }
  .delta-neutral-hero span,
  .delta-core-balance a { display: block; margin-top: 9px; }
  .delta-slide footer { display: block; }
  .delta-slide footer b { display: block; margin-top: 5px; }
}

@media (prefers-reduced-motion: reduce) {
  .option-guide-card { transition: none; }
}