/* VitalDynamics365.com — shared design system */

:root {
  --color-bg: #0b1220;
  --color-bg-alt: #101a2e;
  --color-surface: #141f38;
  --color-surface-2: #182548;
  --color-border: #253356;
  --color-text: #e7ecf7;
  --color-text-dim: #a9b4cc;
  --color-text-faint: #7684a3;
  --color-primary: #4f8cff;
  --color-primary-dim: #2f5fc4;
  --color-accent: #33d6a6;
  --color-warn: #ffb454;
  --radius: 10px;
  --radius-lg: 16px;
  --shadow: 0 10px 30px rgba(6, 10, 20, 0.35);
  --max-width: 1120px;
  --font-body: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
}

@media (prefers-color-scheme: light) {
  :root {
    --color-bg: #f6f8fc;
    --color-bg-alt: #eef1f8;
    --color-surface: #ffffff;
    --color-surface-2: #f1f4fa;
    --color-border: #dde3f0;
    --color-text: #101a2e;
    --color-text-dim: #4a5675;
    --color-text-faint: #6c7794;
    --shadow: 0 10px 30px rgba(20, 30, 60, 0.08);
  }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-body);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--color-primary); text-decoration: none; }
a:hover { text-decoration: underline; }

img, svg { max-width: 100%; }

.wrap {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- Header / Nav ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(11, 18, 32, 0.85);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-border);
}
@media (prefers-color-scheme: light) {
  .site-header { background: rgba(246, 248, 252, 0.9); }
}
.site-header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--color-text);
}
.brand:hover { text-decoration: none; }
.brand-mark {
  width: 30px;
  height: 30px;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: #06101f;
  font-weight: 800;
  font-size: 0.95rem;
}
nav.main-nav {
  display: flex;
  align-items: center;
  gap: 28px;
}
nav.main-nav a {
  color: var(--color-text-dim);
  font-size: 0.95rem;
  font-weight: 500;
}
nav.main-nav a:hover, nav.main-nav a.active { color: var(--color-text); text-decoration: none; }
.nav-cta {
  background: var(--color-primary);
  color: #06101f !important;
  padding: 9px 18px;
  border-radius: 999px;
  font-weight: 600 !important;
}
.nav-cta:hover { background: var(--color-primary-dim); }
.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  color: var(--color-text);
  padding: 8px 10px;
  cursor: pointer;
}

@media (max-width: 820px) {
  nav.main-nav {
    position: absolute;
    top: 68px;
    left: 0;
    right: 0;
    background: var(--color-bg-alt);
    border-bottom: 1px solid var(--color-border);
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    padding: 8px 24px 16px;
    display: none;
  }
  nav.main-nav.open { display: flex; }
  nav.main-nav a { width: 100%; padding: 12px 0; border-bottom: 1px solid var(--color-border); }
  .nav-cta { margin-top: 10px; text-align: center; }
  .nav-toggle { display: inline-flex; }
}

/* ---------- Hero ---------- */
.hero {
  padding: 76px 0 56px;
  background: radial-gradient(1200px 400px at 80% -10%, rgba(79, 140, 255, 0.16), transparent),
              radial-gradient(900px 300px at 0% 0%, rgba(51, 214, 166, 0.12), transparent);
  border-bottom: 1px solid var(--color-border);
}
.eyebrow {
  display: inline-block;
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-accent);
  font-weight: 700;
  margin-bottom: 14px;
}
.hero h1 {
  font-size: clamp(2rem, 4.2vw, 3.1rem);
  line-height: 1.15;
  margin: 0 0 18px;
  max-width: 20ch;
}
.hero p.lead {
  font-size: 1.15rem;
  color: var(--color-text-dim);
  max-width: 62ch;
  margin: 0 0 28px;
}
.hero-actions { display: flex; gap: 14px; flex-wrap: wrap; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 22px;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.95rem;
  border: 1px solid transparent;
  cursor: pointer;
}
.btn-primary { background: var(--color-primary); color: #06101f; }
.btn-primary:hover { background: var(--color-primary-dim); text-decoration: none; }
.btn-ghost { border-color: var(--color-border); color: var(--color-text); }
.btn-ghost:hover { border-color: var(--color-primary); text-decoration: none; }

/* ---------- Sections / layout ---------- */
section { padding: 64px 0; }
.section-tight { padding: 40px 0; }
h2 { font-size: clamp(1.5rem, 2.6vw, 2rem); margin: 0 0 12px; }
h2.section-title { text-align: left; }
.section-intro { color: var(--color-text-dim); max-width: 68ch; margin: 0 0 36px; }

.grid {
  display: grid;
  gap: 22px;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
}
.grid-2 { grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); }

.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 26px;
}
.card h3 { margin: 0 0 10px; font-size: 1.1rem; }
.card p { color: var(--color-text-dim); margin: 0 0 14px; font-size: 0.96rem; }
.card .tag-list { margin-top: 14px; }

.topic-card {
  display: block;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 26px;
  transition: transform 0.15s ease, border-color 0.15s ease;
}
.topic-card:hover { transform: translateY(-3px); border-color: var(--color-primary); text-decoration: none; }
.topic-card .icon { width: 40px; height: 40px; margin-bottom: 14px; color: var(--color-primary); }
.topic-card h3 { color: var(--color-text); margin: 0 0 8px; font-size: 1.08rem; }
.topic-card p { color: var(--color-text-dim); font-size: 0.92rem; margin: 0; }

.tag {
  display: inline-block;
  font-size: 0.75rem;
  padding: 4px 10px;
  border-radius: 999px;
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  color: var(--color-text-dim);
  margin: 0 6px 6px 0;
}

/* ---------- Article / tutorial pages ---------- */
.breadcrumb {
  font-size: 0.85rem;
  color: var(--color-text-faint);
  padding: 18px 0 0;
}
.breadcrumb a { color: var(--color-text-faint); }
.breadcrumb a:hover { color: var(--color-primary); }

.article-header { padding: 28px 0 20px; border-bottom: 1px solid var(--color-border); }
.article-header h1 { font-size: clamp(1.8rem, 3.6vw, 2.5rem); margin: 6px 0 14px; }
.article-meta { color: var(--color-text-faint); font-size: 0.88rem; }

.article-body { max-width: 78ch; padding-top: 36px; }
.article-body h2 { margin-top: 44px; padding-top: 6px; border-top: 1px solid var(--color-border); }
.article-body h2:first-child { border-top: none; margin-top: 0; }
.article-body h3 { margin-top: 28px; font-size: 1.15rem; }
.article-body p { color: var(--color-text-dim); }
.article-body ul, .article-body ol { color: var(--color-text-dim); padding-left: 22px; }
.article-body li { margin-bottom: 8px; }
.article-body strong { color: var(--color-text); }

.callout {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-left: 3px solid var(--color-primary);
  border-radius: var(--radius);
  padding: 18px 20px;
  margin: 26px 0;
  color: var(--color-text-dim);
  font-size: 0.94rem;
}
.callout strong { color: var(--color-text); }
.callout.warn { border-left-color: var(--color-warn); }

pre {
  background: #060a14;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 18px 20px;
  overflow-x: auto;
  margin: 20px 0;
}
@media (prefers-color-scheme: light) { pre { background: #0e1626; } }
code {
  font-family: var(--font-mono);
  font-size: 0.86rem;
  color: #d6e2ff;
}
p code, li code {
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  padding: 1px 6px;
  color: var(--color-text);
}

table {
  width: 100%;
  border-collapse: collapse;
  margin: 20px 0;
  font-size: 0.92rem;
}
th, td {
  text-align: left;
  padding: 10px 14px;
  border-bottom: 1px solid var(--color-border);
  color: var(--color-text-dim);
}
th { color: var(--color-text); font-weight: 600; background: var(--color-surface-2); }

.related-box {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 24px;
  margin-top: 48px;
}
.related-box h3 { margin: 0 0 12px; font-size: 1rem; }
.related-box ul { margin: 0; padding-left: 20px; }

/* ---------- FAQ / interview Q&A ---------- */
.faq-item {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  margin-bottom: 14px;
  overflow: hidden;
}
.faq-question {
  width: 100%;
  text-align: left;
  background: none;
  border: none;
  color: var(--color-text);
  font-weight: 600;
  font-size: 1rem;
  padding: 18px 46px 18px 20px;
  cursor: pointer;
  position: relative;
}
.faq-question::after {
  content: "+";
  position: absolute;
  right: 18px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 1.3rem;
  color: var(--color-primary);
}
.faq-item.open .faq-question::after { content: "\2212"; }
.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.25s ease;
  padding: 0 20px;
  color: var(--color-text-dim);
}
.faq-item.open .faq-answer { padding: 0 20px 20px; }
.faq-answer p:first-child { margin-top: 0; }

.faq-group-title {
  margin-top: 40px;
  margin-bottom: 16px;
  font-size: 1.1rem;
  color: var(--color-text);
}
.faq-group-title:first-of-type { margin-top: 0; }

/* ---------- Case study ---------- */
.stat-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 18px;
  margin: 30px 0;
}
.stat-box {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 18px;
  text-align: center;
}
.stat-box .num { font-size: 1.6rem; font-weight: 700; color: var(--color-primary); }
.stat-box .label { font-size: 0.8rem; color: var(--color-text-faint); margin-top: 4px; }

/* ---------- CTA band ---------- */
.cta-band {
  background: linear-gradient(120deg, var(--color-surface), var(--color-surface-2));
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
  padding: 56px 0;
  text-align: center;
}
.cta-band h2 { margin-bottom: 10px; }
.cta-band p { color: var(--color-text-dim); margin-bottom: 26px; }

/* ---------- Learning path (chapter layout) ---------- */
.learn-wrap {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 32px 24px 0;
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 44px;
  align-items: start;
}
.learn-sidebar {
  position: sticky;
  top: 84px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 18px;
}
.learn-sidebar h4 {
  margin: 0 0 4px;
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-text-faint);
}
.learn-sidebar .learn-category-title {
  font-size: 0.98rem;
  font-weight: 700;
  color: var(--color-text);
  margin: 0 0 14px;
}
.learn-sidebar ol {
  list-style: none;
  margin: 0;
  padding: 0;
  counter-reset: chapter;
}
.learn-sidebar li { counter-increment: chapter; margin-bottom: 2px; }
.learn-sidebar a {
  display: flex;
  gap: 10px;
  align-items: baseline;
  padding: 8px 10px;
  border-radius: 8px;
  color: var(--color-text-dim);
  font-size: 0.88rem;
  line-height: 1.35;
}
.learn-sidebar a::before {
  content: counter(chapter);
  flex: none;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  color: var(--color-text-faint);
  font-size: 0.72rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}
.learn-sidebar a:hover { background: var(--color-surface-2); text-decoration: none; color: var(--color-text); }
.learn-sidebar a.active { background: rgba(79, 140, 255, 0.12); color: var(--color-text); font-weight: 600; }
.learn-sidebar a.active::before { background: var(--color-primary); border-color: var(--color-primary); color: #06101f; }
.learn-sidebar .learn-back {
  display: block;
  margin-top: 14px;
  padding-top: 14px;
  border-top: 1px solid var(--color-border);
  font-size: 0.82rem;
  color: var(--color-text-faint);
}

.learn-content { min-width: 0; }
.chapter-progress {
  font-size: 0.8rem;
  color: var(--color-text-faint);
  margin: 4px 0 0;
}

.chapter-nav {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-top: 48px;
  padding-top: 28px;
  border-top: 1px solid var(--color-border);
}
.chapter-nav a {
  display: block;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 16px 18px;
  color: var(--color-text);
}
.chapter-nav a:hover { border-color: var(--color-primary); text-decoration: none; }
.chapter-nav .dir { display: block; font-size: 0.75rem; color: var(--color-text-faint); margin-bottom: 4px; }
.chapter-nav .next { text-align: right; grid-column: 2; }
.chapter-nav .prev-empty, .chapter-nav .next-empty { visibility: hidden; }

.callout.example .callout-label {
  display: inline-block;
  font-size: 0.72rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--color-accent);
  font-weight: 700;
  margin-bottom: 8px;
}

.course-card {
  position: relative;
  padding-left: 66px;
}
.course-card .course-num {
  position: absolute;
  left: 26px;
  top: 26px;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  color: var(--color-primary);
  font-weight: 700;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 0.9rem;
}
.course-card.soon { opacity: 0.6; }
.course-card .badge-soon {
  display: inline-block;
  font-size: 0.7rem;
  padding: 2px 8px;
  border-radius: 999px;
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  color: var(--color-text-faint);
  margin-left: 8px;
}

@media (max-width: 900px) {
  .learn-wrap { grid-template-columns: 1fr; }
  .learn-sidebar { position: static; }
}

/* ---------- Forms ---------- */
form.contact-form { max-width: 560px; }
.form-row { margin-bottom: 18px; }
.form-row label { display: block; font-size: 0.9rem; font-weight: 600; margin-bottom: 6px; }
.form-row input, .form-row textarea, .form-row select {
  width: 100%;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 12px 14px;
  color: var(--color-text);
  font-family: inherit;
  font-size: 0.95rem;
}
.form-row textarea { min-height: 140px; resize: vertical; }
.form-row input:focus, .form-row textarea:focus, .form-row select:focus {
  outline: none;
  border-color: var(--color-primary);
}

/* ---------- Footer ---------- */
.site-footer {
  border-top: 1px solid var(--color-border);
  padding: 48px 0 32px;
  color: var(--color-text-faint);
  font-size: 0.88rem;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 30px;
  margin-bottom: 30px;
}
.footer-grid h4 { color: var(--color-text); font-size: 0.85rem; margin: 0 0 14px; }
.footer-grid ul { list-style: none; margin: 0; padding: 0; }
.footer-grid li { margin-bottom: 9px; }
.footer-grid a { color: var(--color-text-faint); }
.footer-grid a:hover { color: var(--color-primary); }
.footer-bottom {
  border-top: 1px solid var(--color-border);
  padding-top: 22px;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px;
}
@media (max-width: 720px) {
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

/* ---------- Utility ---------- */
.mt-0 { margin-top: 0; }
.center { text-align: center; }
.visually-hidden {
  position: absolute;
  width: 1px; height: 1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
}