.roof-explainer .roof-logo { padding: 25px 20px 20px; text-align: center; }
.roof-logo img { display: inline-block; height: 23px; width: auto; }
.roof-explainer main { position: relative; }
.roof-explainer .roof-intro { padding: 24px 0 0; border: 0; }
.roof-explainer .roof-details { padding: 35px 0 0; border: 0; }
.roof-audience { color: var(--accent-2); text-align: center; font-size: 12px; font-weight: 600; margin-bottom: 20px; }
.roof-explainer h1 { font-size: clamp(35px,4.6vw,57px); line-height: 1.08; letter-spacing: -.035em; text-align: center; font-weight: 600; margin: 0 auto 20px; }
.roof-explainer h1 span, .roof-definition h2 span, .roof-proof h2 span { color: var(--accent-2); }
.roof-lead { text-align: center; font-size: 18px; line-height: 1.6; color: var(--fg-soft); }
.roof-hero-points { max-width: 535px; margin: 25px auto 0; padding: 0; list-style: none; display: grid; gap: 11px; }
.roof-hero-points li { display: flex; gap: 12px; align-items: flex-start; color: var(--fg-soft); font-size: 15px; line-height: 1.55; }
.roof-hero-points span { color: var(--accent-2); font-weight: 700; }
.roof-button { display: flex; width: fit-content; align-items: center; gap: 16px; margin: 24px auto 40px; padding: 13px 22px; color: white; background: var(--accent); border-radius: 9px; font-size: 14px; font-weight: 600; text-align: center; }
.roof-button:hover { background: #087eda; }
.roof-definition { padding: 28px; border: 1px solid var(--line); border-radius: 15px; background: var(--bg-card); }
.roof-eyebrow { font-size: 10px; font-family: var(--mono); text-transform: uppercase; letter-spacing: .1em; color: var(--accent-2); margin-bottom: 12px; }
.roof-definition h2 { font-size: 23px; line-height: 1.3; letter-spacing: -.02em; font-weight: 600; }
.roof-definition > p:not(.roof-eyebrow) { font-size: 14px; line-height: 1.75; margin-top: 14px; color: var(--fg-soft); }
.roof-maths { padding: 30px 0; margin: 15px 0; text-align: center; border-bottom: 1px solid var(--line); }
.roof-maths h2, .roof-included h2 { font-size: 26px; line-height: 1.25; font-weight: 600; letter-spacing: -.02em; }
.roof-equation { display: flex; justify-content: center; align-items: center; gap: 22px; margin: 23px 0 18px; }
.roof-equation span { font-size: 12px; color: var(--fg-soft); }
.roof-equation strong { display: block; font-size: 31px; color: var(--fg); font-weight: 600; letter-spacing: -.03em; }
.roof-equation span:last-child strong { color: var(--accent-2); }
.roof-equation b { color: var(--fg-mute); font-size: 20px; font-weight: 400; }
.roof-maths > p:not(.roof-eyebrow) { max-width: 570px; margin: 0 auto; font-size: 14px; line-height: 1.7; color: var(--fg-soft); }
.roof-included { padding: 20px 0 30px; }
.roof-included > .roof-eyebrow, .roof-included > h2 { text-align: center; }
.roof-included ul { list-style: none; padding: 0; margin: 25px 0; display: grid; grid-template-columns: 1fr 1fr; gap: 22px 25px; }
.roof-included li { display: flex; gap: 11px; align-items: flex-start; }
.roof-included li > span { color: var(--accent-2); font-weight: 700; }
.roof-included li strong { font-size: 14px; font-weight: 600; }
.roof-included li p { font-size: 13px; color: var(--fg-soft); line-height: 1.65; margin-top: 4px; }
.roof-your-part { text-align: center; padding: 22px 0 0; border-top: 1px solid var(--line); }
.roof-your-part strong { font-size: 17px; font-weight: 500; }
.roof-your-part p { font-size: 14px; color: var(--fg-soft); margin-top: 5px; }
.roof-proof { text-align: center; padding: 28px; border: 1px solid rgba(58,168,255,.32); border-radius: 15px; background: radial-gradient(ellipse at top,rgba(0,140,254,.12),transparent); }
.roof-proof h2 { font-size: 27px; line-height: 1.2; font-weight: 600; letter-spacing: -.025em; }
.roof-proof > p:last-child { max-width: 560px; margin: 15px auto 0; font-size: 14px; line-height: 1.7; color: var(--fg-soft); }
.roof-explainer .roof-book { padding: 45px 0 35px; border: 0; scroll-margin-top: 20px; }
.roof-explainer .roof-book-first { padding-top: 30px; }
.roof-explainer .roof-book-last { padding-top: 30px; border-top: 1px solid var(--line); }
.roof-book-heading { text-align: center; margin-bottom: 24px; }
.roof-book-heading h2 { font-size: 32px; font-weight: 600; letter-spacing: -.025em; line-height: 1.2; }
.roof-book-heading > p:last-child { margin-top: 12px; font-size: 14px; color: var(--fg-soft); line-height: 1.7; }
.roof-calendar { max-width: 960px; height: 760px; margin: 0 auto; border: 1px solid var(--line); border-radius: 16px; overflow: hidden; background: var(--bg-card); }
.roof-calendar-fallback { text-align: center; font-size: 12px; color: var(--fg-mute); margin: 15px 0 0; }
.roof-calendar-fallback a { color: var(--accent-2); text-decoration: underline; text-underline-offset: 3px; }
.roof-explainer .roof-questions { padding: 10px 0 55px; border: 0; }
.roof-questions h2 { font-size: 24px; text-align: center; margin-bottom: 22px; font-weight: 600; letter-spacing: -.02em; }
.roof-questions details { padding: 17px 0; border-bottom: 1px solid var(--line); }
.roof-questions summary { cursor: pointer; font-size: 14px; font-weight: 500; }
.roof-questions summary::marker { color: var(--accent-2); }
.roof-questions details p { margin-top: 12px; color: var(--fg-soft); font-size: 13px; line-height: 1.8; }
.roof-explainer a:focus-visible, .roof-explainer summary:focus-visible { outline: 2px solid var(--accent-2); outline-offset: 5px; }
@media(max-width:600px) {
  .roof-explainer .container, .roof-explainer .container-narrow { padding-left: 20px; padding-right: 20px; }
  .roof-explainer .roof-intro { padding-top: 16px; }
  .roof-audience { font-size: 11px; max-width: 270px; margin-left: auto; margin-right: auto; }
  .roof-lead { font-size: 16px; }
  .roof-hero-points { max-width: 355px; padding: 0 6px; }
  .roof-hero-points li { font-size: 14px; }
  .roof-definition, .roof-proof { padding: 23px 20px; }
  .roof-definition h2 { font-size: 22px; }
  .roof-definition br { display: none; }
  .roof-equation { gap: 10px; }
  .roof-equation strong { font-size: 24px; }
  .roof-equation span { font-size: 10px; }
  .roof-included ul { grid-template-columns: 1fr; gap: 20px; }
  .roof-proof h2 { font-size: 26px; }
  .roof-explainer .roof-book > .container { padding-left: 8px; padding-right: 8px; }
  .roof-book-heading { padding: 0 12px; }
  .roof-calendar { height: 900px; border-radius: 12px; }
  .roof-calendar-fallback { padding: 0 12px; }
}
@media(prefers-reduced-motion:reduce) { html { scroll-behavior: auto; } }