/* ============================================================
   Aerospace MRO Open House 2026 - stylesheet
   Mobile-first. Sizing uses rem/em + clamp() throughout so the
   whole page scales smoothly between phone and desktop widths.
   ============================================================ */

:root {
  /* Abstract aerospace palette */
  --navy-950: #060a17;
  --navy-900: #0a1128;
  --navy-800: #0f1c3f;
  --navy-700: #16264f;
  --navy-600: #1e3363;
  --cyan-400: #4fd9ff;
  --cyan-300: #8ae9ff;
  --blue-500: #3a7dff;
  --amber-400: #ffb454;
  --white: #f5f8ff;
  --grey-300: #b9c4dd;
  --grey-400: #8b98bd;

  --font-display: 'Space Grotesk', 'Segoe UI', system-ui, sans-serif;
  --font-body: 'Inter', 'Segoe UI', system-ui, sans-serif;

  /* Fluid type scale */
  --step-xs:  clamp(0.75rem, 0.7rem + 0.2vw, 0.85rem);
  --step-sm:  clamp(0.875rem, 0.82rem + 0.25vw, 1rem);
  --step-base: clamp(1rem, 0.94rem + 0.3vw, 1.125rem);
  --step-md:  clamp(1.15rem, 1.05rem + 0.5vw, 1.4rem);
  --step-lg:  clamp(1.4rem, 1.2rem + 1vw, 1.9rem);
  --step-xl:  clamp(1.9rem, 1.5rem + 1.8vw, 2.75rem);
  --step-2xl: clamp(2.3rem, 1.7rem + 3vw, 3.75rem);

  --space-2xs: clamp(0.4em, 0.35em + 0.2vw, 0.6em);
  --space-xs:  clamp(0.6em, 0.5em + 0.4vw, 0.9em);
  --space-sm:  clamp(1em, 0.85em + 0.6vw, 1.4em);
  --space-md:  clamp(1.6em, 1.3em + 1vw, 2.2em);
  --space-lg:  clamp(2.4em, 1.9em + 1.8vw, 3.6em);
  --space-xl:  clamp(3.2em, 2.4em + 3vw, 5.5em);

  --radius-md: 0.9rem;
  --radius-lg: 1.4rem;
  --max-width: 75rem;
}

/* ---------- reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--navy-950);
  color: var(--white);
  font-family: var(--font-body);
  font-size: var(--step-base);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
img, svg { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
ul { margin: 0; padding: 0; list-style: none; }
h1, h2, h3, h4 { font-family: var(--font-display); margin: 0 0 var(--space-xs); line-height: 1.15; letter-spacing: -0.01em; }
p { margin: 0 0 var(--space-sm); color: var(--grey-300); }
button, input, textarea, select { font-family: inherit; font-size: 1em; }

.container {
  width: min(100% - clamp(1.5rem, 6vw, 4rem), var(--max-width));
  margin-inline: auto;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.5em;
  font-size: var(--step-xs);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--cyan-300);
  font-weight: 600;
  margin-bottom: var(--space-xs);
}

/* ---------- background: abstract aerospace lines ---------- */
.bg-lines {
  position: fixed;
  inset: 0;
  z-index: -1;
  background:
    radial-gradient(ellipse 60em 40em at 85% -10%, rgba(63, 125, 255, 0.28), transparent 60%),
    radial-gradient(ellipse 50em 35em at 5% 30%, rgba(79, 217, 255, 0.14), transparent 60%),
    linear-gradient(180deg, var(--navy-950), var(--navy-900) 40%, var(--navy-950));
}

/* ---------- header / nav ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  backdrop-filter: blur(0.6em);
  background: rgba(6, 10, 23, 0.75);
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-sm);
  padding-block: 0.9em;
}
.brand {
  display: flex;
  align-items: center;
  gap: 0.6em;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--step-sm);
  color: var(--white);
}
.nav-links { display: none; gap: var(--space-md); font-size: var(--step-sm); color: var(--grey-300); }
.nav-links a:hover { color: var(--cyan-300); }
@media (min-width: 48em) { .nav-links { display: flex; } }

/* ---------- buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5em;
  padding: 0.85em 1.6em;
  border-radius: 0.6em;
  font-weight: 600;
  font-size: var(--step-sm);
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease, background 0.15s ease;
  white-space: nowrap;
}
.btn:active { transform: translateY(1px); }
.btn-primary {
  background: linear-gradient(120deg, var(--cyan-400), var(--blue-500));
  color: var(--navy-950);
  box-shadow: 0 0.6em 1.6em -0.6em rgba(79, 217, 255, 0.55);
}
.btn-primary:hover { box-shadow: 0 0.8em 2em -0.5em rgba(79, 217, 255, 0.75); }
.btn-ghost {
  background: rgba(255, 255, 255, 0.04);
  border-color: rgba(255, 255, 255, 0.18);
  color: var(--white);
}
.btn-ghost:hover { border-color: var(--cyan-300); color: var(--cyan-300); }
.btn-block { width: 100%; }
.btn-row { display: flex; flex-wrap: wrap; gap: var(--space-xs); position: relative; }

/* ---------- add-to-calendar dropdown (native <details>, no JS) ---------- */
.add-to-cal { position: relative; }
.add-to-cal summary {
  list-style: none;
}
.add-to-cal summary::-webkit-details-marker { display: none; }
.add-to-cal summary::after {
  content: '';
  width: 0.5em;
  height: 0.5em;
  border-right: 0.14em solid currentColor;
  border-bottom: 0.14em solid currentColor;
  transform: rotate(45deg);
  margin-left: 0.3em;
  transition: transform 0.15s ease;
}
.add-to-cal[open] summary::after { transform: rotate(-135deg); }
.add-to-cal[open] summary { border-color: var(--cyan-300); color: var(--cyan-300); }
.cal-menu {
  position: absolute;
  top: calc(100% + 0.6em);
  left: 0;
  z-index: 30;
  min-width: 15em;
  padding: 0.5em;
  display: grid;
  gap: 0.2em;
  background: var(--navy-800);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: var(--radius-md);
  box-shadow: 0 1em 2.4em -0.8em rgba(0, 0, 0, 0.7);
}
.cal-menu a {
  display: flex;
  align-items: center;
  gap: 0.6em;
  padding: 0.6em 0.7em;
  border-radius: 0.5em;
  font-size: var(--step-sm);
  color: var(--grey-300);
}
.cal-menu a:hover { background: rgba(255, 255, 255, 0.06); color: var(--cyan-300); }
.cal-icon { font-size: 1.05em; }

/* ---------- hero ---------- */
.hero {
  padding-block: clamp(3.5em, 6vw + 2em, 7em) var(--space-xl);
  position: relative;
}
.hero-grid {
  display: grid;
  gap: var(--space-lg);
  align-items: center;
}
@media (min-width: 56em) {
  .hero-grid { grid-template-columns: 1fr 0.95fr; align-items: start; }
}
.hero h1 {
  font-size: var(--step-2xl);
  background: linear-gradient(120deg, #ffffff 30%, var(--cyan-300));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero .lede { font-size: var(--step-md); color: var(--grey-300); max-width: 38em; }
.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-block: var(--space-md);
}
.meta-chip {
  display: flex;
  align-items: center;
  gap: 0.6em;
  padding: 0.7em 1.1em;
  border-radius: 0.8em;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.08);
  font-size: var(--step-sm);
  color: var(--white);
}
.meta-chip .icon { color: var(--cyan-300); font-size: 1.1em; }

/* ---------- section shell ---------- */
section { padding-block: var(--space-xl); }
.section-head { max-width: 42em; margin-bottom: var(--space-lg); }
.section-head h2 { font-size: var(--step-xl); }
.section-head p { font-size: var(--step-md); }

/* ---------- agenda ---------- */
.agenda-list { display: flex; flex-direction: column; gap: 0; border-left: 2px solid rgba(255,255,255,0.1); margin-left: 0.5em; }
.agenda-item {
  position: relative;
  padding: var(--space-xs) 0 var(--space-xs) var(--space-md);
  display: grid;
  gap: 0.2em;
}
.agenda-item::before {
  content: "";
  position: absolute;
  left: -0.5em;
  top: 1.6em;
  width: 0.9em;
  height: 0.9em;
  border-radius: 50%;
  background: var(--navy-950);
  border: 2px solid var(--cyan-400);
}
.agenda-item.is-highlight::before { background: var(--cyan-400); box-shadow: 0 0 0.8em var(--cyan-400); }
.agenda-time { font-size: var(--step-xs); letter-spacing: 0.08em; text-transform: uppercase; color: var(--cyan-300); font-weight: 700; }
.agenda-title { font-size: var(--step-md); font-weight: 600; color: var(--white); }
.agenda-sub { font-size: var(--step-sm); color: var(--grey-400); margin: 0; }

/* ---------- speakers ---------- */
.grid-3 {
  display: grid;
  gap: var(--space-md);
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 17rem), 1fr));
}
.card {
  background: linear-gradient(180deg, rgba(255,255,255,0.05), rgba(255,255,255,0.02));
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: var(--radius-lg);
  padding: var(--space-md);
  height: 100%;
}
.speaker-card { text-align: left; }
.speaker-avatar {
  width: 5.2em;
  height: 5.2em;
  border-radius: 50%;
  object-fit: cover;
  object-position: center top;
  background: linear-gradient(135deg, var(--cyan-400), var(--blue-500));
  border: 2px solid rgba(255, 255, 255, 0.12);
  box-shadow: 0 0.5em 1.4em -0.6em rgba(0, 0, 0, 0.6);
  margin-bottom: var(--space-sm);
}
.speaker-name { font-size: var(--step-md); margin-bottom: 0.1em; }
.speaker-role { color: var(--cyan-300); font-size: var(--step-sm); font-weight: 600; margin-bottom: var(--space-xs); }
.speaker-bio { font-size: var(--step-sm); margin-bottom: 0; }

/* ---------- companies ---------- */
.company-card { display: flex; flex-direction: column; gap: var(--space-xs); }
.logo-chip {
  display: inline-flex;
  align-items: center;
  background: #ffffff;
  border-radius: 0.6em;
  padding: 0.7em 1.1em;
  box-shadow: 0 0.5em 1.4em -0.6em rgba(0, 0, 0, 0.5);
  margin-bottom: var(--space-xs);
}
.logo-chip img { display: block; width: auto; max-width: 11em; }
.logo-chip-sm { padding: 0.4em 0.75em; border-radius: 0.5em; margin-bottom: 0; }
.company-tagline { font-size: var(--step-xs); text-transform: uppercase; letter-spacing: 0.1em; color: var(--grey-400); margin-bottom: var(--space-xs); }
.company-body { font-size: var(--step-sm); color: var(--grey-300); margin-bottom: 0; }

/* ---------- registration ---------- */
.form-card {
  background: var(--navy-800);
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: var(--radius-lg);
  padding: var(--space-md);
}
.form-row { display: grid; gap: var(--space-xs); margin-bottom: var(--space-sm); }
.form-row.two-col { grid-template-columns: 1fr; }
@media (min-width: 34em) { .form-row.two-col { grid-template-columns: 1fr 1fr; } }
label { font-size: var(--step-sm); color: var(--grey-300); margin-bottom: 0.4em; display: block; font-weight: 500; }
input[type=text], input[type=email], input[type=tel], textarea, select {
  width: 100%;
  padding: 0.85em 1em;
  border-radius: 0.6em;
  border: 1px solid rgba(255,255,255,0.14);
  background: rgba(255,255,255,0.04);
  color: var(--white);
}
input:focus, textarea:focus, select:focus { outline: 2px solid var(--cyan-400); outline-offset: 1px; }
.form-note { font-size: var(--step-xs); color: var(--grey-400); margin-top: var(--space-xs); }
.alert { padding: 0.9em 1.1em; border-radius: 0.7em; font-size: var(--step-sm); margin-bottom: var(--space-sm); }
.alert-success { background: rgba(79, 217, 255, 0.12); border: 1px solid rgba(79, 217, 255, 0.4); color: var(--cyan-300); }
.alert-error { background: rgba(255, 99, 99, 0.12); border: 1px solid rgba(255, 99, 99, 0.4); color: #ff9b9b; }

/* ---------- footer ---------- */
.site-footer { padding-block: var(--space-lg); border-top: 1px solid rgba(255,255,255,0.06); }
.footer-grid {
  display: grid;
  gap: var(--space-md);
  grid-template-columns: 1fr;
}
@media (min-width: 40em) { .footer-grid { grid-template-columns: 1.2fr 1fr 1fr; } }
.footer-logos { display: flex; flex-wrap: wrap; gap: var(--space-xs); align-items: center; }
.footer-note { font-size: var(--step-xs); color: var(--grey-400); margin-top: var(--space-md); }

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