/* ==========================================================================
   Guided Biofilm Therapy — reference stylesheet
   Reference implementation only. Figma node 197:36 ("Final Page") is the
   authoritative visual source — see README.md before making changes.
   ========================================================================== */

/* ---------- Design tokens ---------- */
:root {
  /* Color */
  --color-navy: #14313d;
  --color-body: #4b5b6b;
  --color-teal: #4a8b8c;
  --color-teal-dark: #1e4252;
  --color-white: #ffffff;

  --color-bg-benefits: #edf7f5;
  --color-bg-what-is-gbt: #0b3846;
  --color-bg-how-it-works: rgba(227, 170, 177, 0.1);
  --color-bg-cta: #14313d;

  --color-icon-bg: #e6efef;
  --color-pink-pill: rgba(227, 170, 177, 0.3);
  --color-pink-text: #4d2429;
  --color-pink-eyebrow-bg: rgba(227, 170, 177, 0.24);
  --color-gray-eyebrow-bg: rgba(206, 206, 206, 0.32);
  --color-teal-eyebrow-bg: rgba(74, 139, 140, 0.2);
  --color-light-eyebrow-bg: rgba(255, 255, 255, 0.7);

  --border-card: #cecece;
  --border-faq: #e3ddd2;

  /* Type */
  --font-body: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  --font-icon: 'Material Symbols Rounded';

  /* Layout */
  --container-max: 1280px;
  --container-padding: 24px;
  --radius-pill: 999px;

  /* Breakpoints (documented in README):
     desktop: > 900px (matches Figma "Final Page", node 197:36)
     tablet:  601px – 900px (derived from reference frame 211:1103, 753px canvas)
     mobile:  <= 600px (derived from reference frame 211:776, 378px canvas) */
}

/* ---------- Reset / base ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-body);
  color: var(--color-body);
  background: var(--color-white);
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; display: block; }
ul { list-style: none; margin: 0; padding: 0; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; background: none; border: none; cursor: pointer; padding: 0; }
h1, h2, h3, p { margin: 0; font-weight: 400; font-size: inherit; }

.visually-hidden {
  position: absolute;
  width: 1px; height: 1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
}

/* ---------- Shared components ---------- */
.eyebrow {
  display: inline-flex;
  align-items: center;
  padding: 8px 16px;
  border-radius: var(--radius-pill);
  background: var(--color-teal-eyebrow-bg);
  color: var(--color-navy);
  font-size: 13px;
  font-weight: 400;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}
.eyebrow--light { background: var(--color-light-eyebrow-bg); }
.eyebrow--gray { background: var(--color-gray-eyebrow-bg); }
.eyebrow--pink { background: var(--color-pink-eyebrow-bg); color: var(--color-pink-text); }

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 16px 32px;
  border-radius: var(--radius-pill);
  font-size: 16px;
  font-weight: 500;
  white-space: nowrap;
}
.button--primary { background: var(--color-teal-dark); color: var(--color-white); }
.button--white { background: var(--color-white); color: var(--color-navy); font-size: 18px; }

.link-arrow {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 16px;
  color: var(--color-teal-dark);
  border-bottom: 1px solid var(--color-teal-dark);
  padding-bottom: 2px;
}
.link-arrow .material-symbols-rounded { font-size: 18px; }
.link-arrow--light {
  color: rgba(255, 255, 255, 0.9);
  border-bottom-color: rgba(255, 255, 255, 0.9);
}

.material-symbols-rounded {
  font-family: var(--font-icon);
  font-weight: 400;
  font-style: normal;
  line-height: 1;
  display: inline-block;
}

section > .eyebrow,
section h2 {
  text-align: center;
}

/* ==========================================================================
   HERO
   ========================================================================== */
.hero { background: var(--color-white); padding: 64px var(--container-padding); }
.hero__inner {
  max-width: var(--container-max);
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr 1fr;
  align-items: center;
  gap: 48px;
}
.hero__heading {
  font-size: 48px;
  font-weight: 500;
  line-height: 1.18;
  letter-spacing: -0.02em;
  color: var(--color-navy);
  margin-bottom: 24px;
}
.hero__heading em { font-style: italic; color: var(--color-teal); }
.hero__description { font-size: 16px; line-height: 1.44; margin-bottom: 32px; max-width: 34em; }
.hero__actions { display: flex; align-items: center; gap: 24px; flex-wrap: wrap; }

.hero__media {
  width: 100%;
  max-width: 620px;
  margin: 0 auto;
}
.hero__image {
  width: 100%;
  height: auto;
  object-fit: contain;
}

/* ==========================================================================
   WHAT IS GBT
   ========================================================================== */
.what-is-gbt { background: var(--color-bg-what-is-gbt); padding: 80px var(--container-padding); position: relative; }
.what-is-gbt__inner {
  max-width: var(--container-max);
  margin: 0 auto;
  display: grid;
  grid-template-columns: 0.9fr 1fr;
  gap: 64px;
  align-items: start;
}
/* Transparent device cutout — intentionally bleeds above the section's own
   top edge into the white Hero section above it (approved Figma composition).
   No card, fill, border, or radius: the dark teal background shows through
   around the device on all sides. */
.what-is-gbt__media { margin-top: -132px; }
.what-is-gbt__image { width: 100%; height: auto; display: block; }
.what-is-gbt__content { display: flex; flex-direction: column; align-items: flex-start; gap: 20px; }
.what-is-gbt__heading {
  font-size: 36px;
  font-weight: 500;
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--color-white);
  text-align: left;
}
.what-is-gbt__description { display: flex; flex-direction: column; gap: 16px; color: rgba(255, 255, 255, 0.78); font-size: 16px; line-height: 1.53; }

/* ==========================================================================
   BENEFITS
   ========================================================================== */
.benefits { background: var(--color-bg-benefits); padding: 80px var(--container-padding); display: flex; flex-direction: column; align-items: center; gap: 24px; }
.benefits__heading {
  max-width: 720px;
  font-size: 40px;
  font-weight: 500;
  line-height: 1.27;
  letter-spacing: -0.02em;
  color: var(--color-navy);
  text-align: center;
}
.benefits__heading em { font-style: italic; color: var(--color-teal); }

.benefit-cards {
  max-width: var(--container-max);
  width: 100%;
  margin-top: 40px;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.benefit-card {
  background: rgba(255, 255, 255, 0.6);
  border: 1px solid rgba(74, 139, 140, 0.8);
  border-radius: 32px;
  padding: 40px 40px 48px;
  text-align: center;
}
.benefit-card__icon {
  width: 96px;
  height: 96px;
  margin: 0 auto 24px;
  border-radius: 50%;
  background: var(--color-icon-bg);
  display: grid;
  place-items: center;
}
.benefit-card__icon img { width: 56px; height: 56px; }
.benefit-card__icon .material-symbols-rounded { font-size: 56px; color: var(--color-navy); }
.benefit-card__heading { font-size: 18px; font-weight: 700; color: var(--color-body); line-height: 1.28; margin-bottom: 12px; }
.benefit-card__description { font-size: 16px; line-height: 1.44; color: var(--color-body); }

/* ==========================================================================
   WHO BENEFITS
   ========================================================================== */
.who-benefits {
  background: var(--color-white);
  display: grid;
  grid-template-columns: 1fr 1fr;
  align-items: center;
}
.who-benefits__media { aspect-ratio: 777 / 598; overflow: hidden; }
.who-benefits__media img { width: 100%; height: 100%; object-fit: cover; }
.who-benefits__content {
  padding: 64px var(--container-padding);
  max-width: 560px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 24px;
}
.who-benefits__heading {
  font-size: 40px;
  font-weight: 500;
  letter-spacing: -0.02em;
  color: var(--color-navy);
  text-align: left;
}
.who-benefits__heading em { font-style: normal; color: var(--color-teal); }
.who-benefits__list { display: flex; flex-direction: column; gap: 12px; width: 100%; }
.who-benefits__list li {
  display: flex;
  align-items: center;
  gap: 16px;
  font-size: 16px;
  color: var(--color-body);
}
.who-benefits__list .material-symbols-rounded { color: var(--color-teal); font-size: 24px; }
.who-benefits__callout { font-size: 16px; line-height: 1.44; }

/* ==========================================================================
   HOW IT WORKS
   ========================================================================== */
.how-it-works { background: var(--color-bg-how-it-works); padding: 80px 0; overflow: hidden; }
.how-it-works__header {
  max-width: var(--container-max);
  margin: 0 auto 40px;
  padding: 0 var(--container-padding);
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 24px;
  flex-wrap: wrap;
}
.how-it-works__heading-group { display: flex; flex-direction: column; align-items: flex-start; gap: 16px; max-width: 640px; }
.how-it-works__heading { font-size: 40px; font-weight: 500; letter-spacing: -0.02em; color: var(--color-navy); text-align: left; }
.how-it-works__description { font-size: 16px; line-height: 1.49; }
.how-it-works__nav { display: flex; gap: 12px; }
.carousel-button {
  width: 48px; height: 48px;
  border-radius: 50%;
  border: 1px solid var(--border-card);
  display: grid;
  place-items: center;
  color: var(--color-teal-dark);
}
.carousel-button--active { background: rgba(227, 170, 177, 0.2); }
.carousel-button:disabled { opacity: 0.35; cursor: not-allowed; }

.step-cards {
  display: flex;
  gap: 25px;
  padding: 0 var(--container-padding);
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  scrollbar-width: none;
}
.step-cards::-webkit-scrollbar { display: none; }
.step-card {
  scroll-snap-align: start;
  flex: 0 0 355px;
  aspect-ratio: 1 / 1;
  background: #fff;
  border-radius: 50%;
  box-shadow: 0 12px 10px rgba(77, 36, 41, 0.1);
  padding: 66px 40px 25px;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}
.step-card__badge {
  display: inline-flex;
  padding: 6px 16px;
  border-radius: var(--radius-pill);
  background: var(--color-pink-pill);
  color: var(--color-pink-text);
  font-size: 13px;
  letter-spacing: 0.06em;
  margin-bottom: 16px;
}
.step-card__heading { font-size: 32px; font-weight: 500; letter-spacing: -0.02em; color: var(--color-navy); margin-bottom: 12px; }
.step-card__reg { font-size: 24px; }
.step-card__description { font-size: 14px; line-height: 1.65; margin-bottom: auto; }
.step-card__counter {
  border-top: 1px solid var(--border-card);
  padding-top: 16px;
  margin-top: 16px;
  width: 100%;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--color-pink-text);
}

.how-it-works__trademark {
  max-width: var(--container-max);
  margin: 32px auto 0;
  padding: 0 var(--container-padding);
  font-size: 12px;
  text-align: center;
}

/* ==========================================================================
   FAQ
   ========================================================================== */
.faq { background: var(--color-white); padding: 80px var(--container-padding); max-width: var(--container-max); margin: 0 auto; }
.faq__top { display: flex; align-items: flex-end; justify-content: space-between; gap: 24px; flex-wrap: wrap; margin-bottom: 24px; }
.faq__heading-group { display: flex; flex-direction: column; align-items: flex-start; gap: 20px; }
.faq__heading { font-size: 40px; font-weight: 500; letter-spacing: -0.02em; color: var(--color-navy); text-align: left; }
.faq__toggle-all {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 16px;
  color: var(--color-teal-dark);
  border-bottom: 1px solid var(--color-teal-dark);
  padding-bottom: 2px;
}
.faq__toggle-all .material-symbols-rounded { transition: transform 0.2s ease; }
.faq__toggle-all[data-state="open"] .material-symbols-rounded { transform: rotate(180deg); }

.faq__list { border-top: 1px solid var(--border-faq); }
.faq-item { border-bottom: 1px solid var(--border-faq); }
.faq-item__question { margin: 0; }
.faq-item__trigger {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 28px 0;
  font-size: 20px;
  font-weight: 400;
  color: var(--color-navy);
  text-align: left;
}
.faq-item__icon {
  flex-shrink: 0;
  width: 40px; height: 40px;
  border-radius: 50%;
  border: 1px solid var(--color-teal-dark);
  display: grid;
  place-items: center;
  color: var(--color-teal-dark);
}
.faq-item__icon .material-symbols-rounded { transition: transform 0.2s ease; }
.faq-item__trigger[aria-expanded="true"] .faq-item__icon {
  background: var(--color-teal-dark);
  color: var(--color-white);
}
.faq-item__trigger[aria-expanded="true"] .faq-item__icon .material-symbols-rounded { transform: rotate(180deg); }
.faq-item__answer { padding: 0 56px 28px 0; font-size: 14px; line-height: 1.7; }
.faq-item__answer[hidden] { display: none; }

/* ==========================================================================
   CTA
   ========================================================================== */
.cta {
  background: var(--color-bg-cta);
  padding: 64px var(--container-padding);
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
}
.cta__heading { font-size: 40px; font-weight: 500; letter-spacing: -0.02em; color: var(--color-white); }
.cta__description { font-size: 16px; color: rgba(255, 255, 255, 0.78); max-width: 40em; }
.cta__actions { display: flex; align-items: center; gap: 20px; margin-top: 16px; flex-wrap: wrap; justify-content: center; }

/* ==========================================================================
   RESPONSIVE
   Breakpoints derived from Figma reference frames 211:1103 (753px = tablet)
   and 211:776 (378px = mobile). See README "Responsive breakpoints" for the
   full rationale.
   ========================================================================== */

/* ---- Tablet: <= 900px ---- */
@media (max-width: 900px) {
  .hero__inner { grid-template-columns: 1fr; }
  .hero__media { order: -1; max-width: 420px; }
  .hero__heading { font-size: 36px; }

  .what-is-gbt__inner { grid-template-columns: 1fr; gap: 24px; }
  .what-is-gbt__media { order: -1; max-width: 360px; margin: -100px auto 0; }
  .what-is-gbt__content { align-items: center; text-align: center; }
  .what-is-gbt__heading, .what-is-gbt__content { text-align: center; }

  .benefit-cards { grid-template-columns: repeat(2, 1fr); }

  .who-benefits { grid-template-columns: 1fr; }
  .who-benefits__media { aspect-ratio: 16 / 10; }
  .who-benefits__content { max-width: none; align-items: center; text-align: center; }
  .who-benefits__heading { text-align: center; }
  .who-benefits__list li { justify-content: center; }

  .cta__actions { flex-direction: column; }
}

/* ---- Mobile: <= 600px ---- */
@media (max-width: 600px) {
  .hero, .what-is-gbt, .benefits, .how-it-works, .faq, .cta { padding-top: 48px; padding-bottom: 48px; }

  .hero__heading { font-size: 30px; }
  .hero__actions { flex-direction: column; align-items: flex-start; gap: 16px; }

  .what-is-gbt__heading { font-size: 30px; }

  .benefits__heading { font-size: 30px; }
  .benefit-cards { grid-template-columns: 1fr; max-width: 360px; margin-left: auto; margin-right: auto; }

  .who-benefits__heading { font-size: 30px; }

  .how-it-works__header { flex-direction: column; align-items: flex-start; }
  .how-it-works__heading { font-size: 30px; }
  .step-card { flex-basis: 300px; padding: 56px 32px 20px; }

  .faq__top { flex-direction: column; align-items: flex-start; }
  .faq__heading { font-size: 30px; }
  .faq-item__trigger { font-size: 17px; }

  .cta__heading { font-size: 30px; }
}