/* Philadelphia Helicopter Corporation — landing page styles */

:root {
  --blue: #1F5EFF;
  --blue-deep: #1449D6;
  --white: #FFFFFF;
  --pale: #EAF0FF;
  --navy: #0F2461;
  --ink: #1F2937;
  --slate: #52616B;
  --line: #D3DDF5;
  --line-navy: rgba(255, 255, 255, 0.18);
  --on-accent: #FFFFFF;
  --muted-on-dark: #B7C6D6;
  --header-bg: rgba(255, 255, 255, 0.96);
  --card-bg: #FFFFFF;
  --card-text: #1F2937;
  --contact-bg: #1F5EFF;
  --contact-text: #FFFFFF;
  --on-dark-text: #FFFFFF;
  --on-dark-btn-bg: #FFFFFF;
  --on-dark-btn-text: #1F5EFF;
  --footer-knot: #FFFFFF;
  --sec-btn-border: rgba(255, 255, 255, 0.7);
  --sans: "IBM Plex Sans", "Helvetica Neue", Helvetica, Arial, sans-serif;
  --mono: "IBM Plex Mono", "SFMono-Regular", Menlo, Consolas, monospace;
  --wrap: 1200px;
  --gutter: 40px;
  --section: 104px;
  --knot-bg: var(--white);
}


*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 88px; -webkit-text-size-adjust: 100%; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }
body {
  margin: 0;
  font-family: var(--sans);
  font-weight: 400;
  font-size: 18px;
  line-height: 1.6;
  color: var(--ink);
  background: var(--white);
  font-feature-settings: "tnum" 1;
}
img, video { max-width: 100%; height: auto; display: block; }
a { color: var(--blue); text-decoration-thickness: 1px; text-underline-offset: 3px; }
a:hover { color: var(--blue-deep); }
:focus-visible { outline: 2px solid var(--blue); outline-offset: 3px; border-radius: 2px; }
.on-dark :focus-visible { outline-color: var(--white); }
button { font: inherit; }

h1, h2, h3 { font-weight: 300; margin: 0; letter-spacing: -0.01em; text-wrap: pretty; }
h1 { font-size: 60px; line-height: 1.08; }
h2 { font-size: 42px; line-height: 1.14; }
h3 { font-size: 26px; line-height: 1.3; font-weight: 400; }
h4 { font-size: 19px; line-height: 1.4; font-weight: 500; margin: 0; }
p { margin: 0; }
.lead { font-size: 21px; line-height: 1.5; }
.measure { max-width: 66ch; }
.note { font-size: 15px; line-height: 1.5; color: var(--slate); }
.caption { font-family: var(--mono); font-size: 13px; line-height: 1.5; color: var(--slate); }
.on-dark .note, .on-dark .caption { color: var(--muted-on-dark); }
.stack > * + * { margin-top: 24px; }
.stack-sm > * + * { margin-top: 12px; }
.stack-lg > * + * { margin-top: 40px; }
.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 var(--gutter); }
section { padding: var(--section) 0; }
.pale { background: var(--pale); }
.navy { background: var(--navy); color: var(--on-dark-text); }
.blue { background: var(--contact-bg); color: var(--contact-text); }
.on-dark h1, .on-dark h2, .on-dark h3 { color: var(--on-dark-text); }
.on-dark a { color: var(--on-dark-text); }
.on-dark a:hover { opacity: 0.8; }
.blue.on-dark, .blue.on-dark h2, .blue.on-dark h3, .blue.on-dark a { color: var(--contact-text); }
.visually-hidden { position: absolute !important; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }

/* Buttons */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  min-height: 46px; padding: 10px 20px; border-radius: 4px;
  font-size: 16px; font-weight: 500; line-height: 1.2; text-decoration: none; cursor: pointer;
  border: 1px solid transparent; transition: background-color 150ms ease, color 150ms ease, border-color 150ms ease;
}
.btn-primary { background: var(--blue); color: var(--on-accent); border-color: var(--blue); }
.btn-primary:hover { background: var(--blue-deep); border-color: var(--blue-deep); color: var(--on-accent); }
.btn-secondary { background: transparent; color: var(--blue); border-color: var(--blue); }
.btn-secondary:hover { background: var(--pale); color: var(--blue-deep); }
.on-dark .btn-primary { background: var(--on-dark-btn-bg); color: var(--on-dark-btn-text); border-color: var(--on-dark-btn-bg); }
.on-dark .btn-primary:hover { opacity: 0.88; }
.on-dark .btn-secondary { color: var(--on-dark-text); border-color: var(--sec-btn-border); }
.on-dark .btn-secondary:hover { background: rgba(255,255,255,0.1); color: var(--on-dark-text); }
.cta-row { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; }
.link-quiet { color: var(--slate); text-decoration: none; }
.link-quiet:hover { color: var(--ink); text-decoration: underline; }
.text-link { font-weight: 500; }

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 20; background: var(--header-bg);
  backdrop-filter: saturate(140%) blur(8px); border-bottom: 1px solid var(--line);
}
.header-inner { display: flex; align-items: center; gap: 32px; min-height: 72px; }
.brand { display: inline-flex; align-items: center; gap: 12px; color: var(--ink); text-decoration: none; }
.brand-name { font-size: 16px; font-weight: 500; line-height: 1.2; letter-spacing: 0.005em; }
.knot { width: 34px; height: 34px; color: var(--blue); flex: none; }
.site-nav { display: flex; gap: 26px; margin-left: auto; }
.site-nav a { font-size: 15px; color: var(--ink); text-decoration: none; }
.site-nav a:hover { color: var(--blue); }
.header-actions { display: flex; align-items: center; gap: 22px; }
.header-actions .link-quiet { font-size: 15px; }
.header-actions .btn { min-height: 40px; padding: 8px 16px; font-size: 15px; }
.menu-toggle { display: none; margin-left: auto; background: none; border: 1px solid var(--line); border-radius: 4px; padding: 8px 12px; font-size: 15px; color: var(--ink); cursor: pointer; }

/* Hero */
.hero { padding: 48px 0 56px; min-height: calc(100vh - 72px); min-height: calc(100svh - 72px); display: flex; align-items: center; }
.hero > .wrap { width: 100%; }
.hero-grid { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 56px; align-items: center; }
.hero h1 span { display: block; color: var(--blue); font-weight: 300; }
.hero .lead { max-width: 40ch; }
.evidence-link { display: inline-flex; align-items: center; gap: 8px; font-size: 16px; font-weight: 500; text-decoration: none; }
.evidence-link:hover { text-decoration: underline; }
.evidence-link svg { width: 16px; height: 16px; }
.metrics { display: grid; grid-template-columns: repeat(3, auto); justify-content: start; gap: 36px; margin: 0; padding-top: 28px; border-top: 1px solid var(--line); }
.metrics dt { font-size: 24px; line-height: 1.15; font-weight: 400; color: var(--ink); white-space: nowrap; }
.metrics dd { margin: 6px 0 0; font-size: 14px; line-height: 1.4; color: var(--slate); }
.hero-figure { margin: 0; }
.hero-media { width: 100%; height: auto; background: var(--pale); border: 1px solid var(--line); }
.hero-figure figcaption { margin-top: 12px; }

/* Full-width photo bands */
.photo-band { padding: 0; }
.photo-band figure { margin: 0; position: relative; }
.photo-band img { width: 100%; height: auto; }
.photo-title { position: absolute; top: 40px; right: var(--gutter); max-width: 60%; text-align: right; font-size: 60px; line-height: 1.08; font-weight: 300; letter-spacing: -0.01em; color: var(--blue); text-wrap: balance; opacity: 0; transform: translateY(14px); transition: opacity 700ms ease, transform 700ms ease; }
.photo-title.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) { .photo-title { opacity: 1; transform: none; transition: none; } }
.photo-frame { border: 1px solid var(--line); background: #FFFFFF; }

/* Section heading blocks */
.section-head { max-width: 30ch; }
.two-col { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 64px; align-items: start; }
.two-col.tight { gap: 48px; }

/* Economics: operating cost callout */
.banner-section { padding: 80px 0; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.banner { display: grid; grid-template-columns: auto minmax(0, 1fr); gap: 72px; align-items: start; }
.banner .stack > * + * { margin-top: 20px; }
.big-figure { font-size: 128px; line-height: 1; font-weight: 300; color: var(--blue); letter-spacing: -0.03em; }
.big-figure-label { font-size: 18px; color: var(--ink); margin-top: 8px; }
.big-figure-label .tag { font-family: var(--mono); font-size: 13px; color: var(--slate); margin-left: 10px; }
.statements { list-style: none; margin: 0; padding: 0; display: grid; gap: 18px; }
.statements li { padding-left: 20px; border-left: 2px solid var(--blue); font-size: 17px; line-height: 1.55; }
.statements strong { font-weight: 500; }

/* Comparison table */
.table-wrap { overflow-x: auto; }
table.compare { width: 100%; border-collapse: collapse; font-size: 17px; }
table.compare caption { text-align: left; font-family: var(--mono); font-size: 13px; color: var(--slate); padding: 0 0 12px; }
table.compare th, table.compare td { text-align: left; padding: 16px 20px 16px 0; border-bottom: 1px solid var(--line); vertical-align: top; }
table.compare th { font-size: 14px; font-weight: 500; color: var(--slate); border-bottom-color: var(--ink); }
table.compare th:last-child, table.compare td:last-child { padding-right: 0; }
table.compare tr.highlight td { background: var(--pale); font-weight: 500; }
table.compare tr.highlight td:first-child { padding-left: 16px; }
table.compare tr.highlight td:last-child { padding-right: 16px; }
table.compare .basis { display: block; font-size: 14px; font-weight: 400; color: var(--slate); }
details.disclosure { border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
details.disclosure summary { cursor: pointer; padding: 14px 0; font-size: 16px; font-weight: 500; list-style: none; display: flex; align-items: center; justify-content: space-between; }
details.disclosure summary::-webkit-details-marker { display: none; }
details.disclosure summary::after { content: ""; width: 10px; height: 10px; border-right: 1.5px solid currentColor; border-bottom: 1.5px solid currentColor; transform: rotate(45deg); transition: transform 150ms ease; margin-right: 4px; }
details.disclosure[open] summary::after { transform: rotate(225deg); }
details.disclosure .disclosure-body { padding: 0 0 18px; font-size: 16px; color: var(--slate); max-width: 72ch; }

/* Flight video */
.player { position: relative; max-width: 1040px; margin-left: auto; margin-right: auto; background: #000; aspect-ratio: 832 / 464; }
.player video { width: 100%; height: 100%; object-fit: contain; }
.player .play {
  position: absolute; inset: 0; width: 100%; height: 100%; display: flex; align-items: center; justify-content: center; gap: 12px;
  background: rgba(16,42,67,0.25); color: var(--white); border: 0; cursor: pointer; font-size: 17px; font-weight: 500;
}
.player .play:hover { background: rgba(16,42,67,0.4); }
.player .play svg { width: 56px; height: 56px; }
.player .play[hidden] { display: none; }
.results { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 32px; margin: 0; padding: 32px 0 0; border-top: 1px solid var(--line-navy); }
.results dt { font-size: 40px; line-height: 1.1; font-weight: 300; }
.results dd { margin: 8px 0 0; font-size: 15px; line-height: 1.45; color: var(--muted-on-dark); }
.links-row { display: flex; flex-wrap: wrap; gap: 24px; font-size: 16px; }

/* Stella 3 */
.specs { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 32px; margin: 0; padding: 32px 0 0; border-top: 1px solid var(--line); }
.specs dt { font-family: var(--mono); font-size: 13px; color: var(--slate); }
.specs dd { margin: 8px 0 0; }
.specs .value { font-size: 32px; line-height: 1.15; font-weight: 300; color: var(--ink); }
.specs .qual { display: block; font-size: 14px; line-height: 1.4; color: var(--slate); margin-top: 6px; }
.features { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 40px; }
.features p { margin-top: 8px; font-size: 17px; color: var(--slate); }
.priorities { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 32px; }
.priorities li { padding-top: 16px; border-top: 1px solid var(--line); font-size: 17px; line-height: 1.55; }
.priorities strong { display: block; font-weight: 500; margin-bottom: 4px; }
.concept { margin: 0; }
.concept img { width: 100%; height: auto; }

/* Founders */
.profiles { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 48px; }
.profile { display: grid; grid-template-columns: 168px minmax(0, 1fr); gap: 28px; align-items: start; }
.profile img { width: 168px; aspect-ratio: 4 / 5; object-fit: cover; border: 1px solid var(--line); background: var(--card-bg); }
.profile h3 { font-size: 22px; font-weight: 500; }
.profile .role { font-size: 15px; color: var(--slate); margin-top: 4px; }
.profile .bio { margin-top: 14px; font-size: 16px; line-height: 1.6; }
.profile .credit { margin-top: 12px; }

/* Applications */
.app-feature { display: grid; grid-template-columns: 56px minmax(0, 1fr); gap: 24px; padding: 32px; border: 1px solid var(--line); background: var(--pale); }
.app-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 24px; }
.app-card { display: grid; grid-template-columns: 40px minmax(0, 1fr); gap: 20px; padding: 28px; border: 1px solid var(--line); background: var(--card-bg); }
.icon { width: 40px; height: 40px; color: var(--blue); }
.app-feature .icon { width: 56px; height: 56px; }
.app-card p, .app-feature p { margin-top: 8px; font-size: 16px; color: var(--ink); }
.app-card .text-link, .app-feature .text-link { display: inline-block; margin-top: 14px; font-size: 15px; }
.app-card .demand { margin-top: 12px; font-size: 15px; color: var(--slate); }

/* Heavy loads */
.examples { margin: 0; padding-left: 20px; font-size: 17px; line-height: 1.55; }
.examples li + li { margin-top: 8px; }
.field-figure { margin-left: 0; margin-right: 0; }
.field-figure img { width: 100%; height: auto; border: 1px solid var(--line); }
.field-figure figcaption { margin-top: 12px; }

/* FAQ */
.faq { border-top: 1px solid var(--line); }
.faq details { border-bottom: 1px solid var(--line); }
.faq summary { cursor: pointer; padding: 22px 0; font-size: 20px; font-weight: 400; list-style: none; display: flex; justify-content: space-between; align-items: center; gap: 24px; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: ""; flex: none; width: 10px; height: 10px; border-right: 1.5px solid currentColor; border-bottom: 1.5px solid currentColor; transform: rotate(45deg); transition: transform 150ms ease; margin-right: 6px; }
.faq details[open] summary::after { transform: rotate(225deg); }
.faq .answer { padding: 0 0 24px; max-width: 70ch; font-size: 17px; color: var(--slate); }

/* Inquiry */
.panels { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 24px; }
.panel { background: var(--card-bg); color: var(--card-text); padding: 36px; display: flex; flex-direction: column; gap: 14px; align-items: flex-start; }
.blue.on-dark .panel h3, .panel h3 { color: var(--card-text); font-size: 24px; }
.panel p { color: var(--slate); font-size: 16px; flex: 1; }
.panel .btn { margin-top: 8px; }
.direct { font-size: 16px; }
.direct a { color: var(--contact-text); font-weight: 500; }

/* Footer */
.site-footer { padding: 56px 0 40px; font-size: 15px; }
.footer-grid { display: grid; grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr) minmax(0, 1fr); gap: 40px; align-items: start; }
.site-footer .brand { color: var(--on-dark-text); }
.site-footer .knot { color: var(--footer-knot); }
.site-footer .tag { margin-top: 14px; color: var(--muted-on-dark); }
.site-footer ul { list-style: none; margin: 0; padding: 0; display: grid; gap: 10px; }
.site-footer a { color: var(--on-dark-text); text-decoration: none; }
.site-footer a:hover { text-decoration: underline; }
.site-footer .small { margin-top: 40px; padding-top: 24px; border-top: 1px solid var(--line-navy); font-size: 13px; color: var(--muted-on-dark); max-width: 80ch; }

/* Dialog forms */
dialog.form-dialog { border: 0; padding: 0; width: min(640px, 100vw); max-height: 100vh; background: var(--card-bg); color: var(--card-text); box-shadow: 0 24px 64px rgba(16,42,67,0.3); }
dialog.form-dialog::backdrop { background: rgba(16,42,67,0.55); }
.dialog-inner { padding: 40px; }
.dialog-head { display: flex; justify-content: space-between; align-items: flex-start; gap: 24px; }
.dialog-head h2 { font-size: 30px; }
.close { background: none; border: 1px solid var(--line); border-radius: 4px; width: 40px; height: 40px; cursor: pointer; color: var(--ink); flex: none; display: inline-flex; align-items: center; justify-content: center; }
.close:hover { background: var(--pale); }
.close svg { width: 16px; height: 16px; }
form .fields { display: grid; gap: 18px; margin-top: 24px; }
.field { display: grid; gap: 6px; }
.field label { font-size: 15px; font-weight: 500; }
.field .help { font-size: 13px; color: var(--slate); }
.field input, .field select, .field textarea { width: 100%; font: inherit; font-size: 16px; padding: 10px 12px; border: 1px solid var(--line); border-radius: 4px; background: var(--card-bg); color: var(--card-text); min-height: 44px; }
.field textarea { min-height: 120px; resize: vertical; }
.field input:focus, .field select:focus, .field textarea:focus { outline: 2px solid var(--blue); outline-offset: 1px; border-color: var(--blue); }
.field.invalid input, .field.invalid select, .field.invalid textarea { border-color: #B42318; }
.field .error { font-size: 13px; color: #B42318; }
.field-row { display: grid; grid-template-columns: minmax(0, 1fr) 120px; gap: 12px; }
.form-foot { display: flex; flex-wrap: wrap; align-items: center; gap: 16px; margin-top: 24px; }
.form-status { margin-top: 20px; font-size: 16px; padding: 14px 16px; border: 1px solid var(--line); background: var(--pale); }
.form-status.error { border-color: #F0C5C0; background: #FDF2F1; }
.form-status[hidden] { display: none; }
.privacy-line { font-size: 13px; color: var(--slate); }
.hp { position: absolute; left: -9999px; width: 1px; height: 1px; opacity: 0; }

/* Entrance motion */
.reveal { opacity: 0; transform: translateY(12px); transition: opacity 260ms ease, transform 260ms ease; }
.reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
}
[data-noreveal] .reveal, [data-noreveal] .photo-title { opacity: 1; transform: none; transition: none; }
html[data-noreveal] { scroll-behavior: auto; }
[data-noreveal] .hero { min-height: 0; padding: 72px 0 64px; }

/* Responsive */
@media (max-width: 1080px) {
  h1 { font-size: 50px; }
  h2 { font-size: 36px; }
  .photo-title { font-size: 44px; }
  .hero-grid { grid-template-columns: minmax(0, 1fr); gap: 40px; }
  .hero .lead { max-width: 60ch; }
  .two-col { grid-template-columns: minmax(0, 1fr); gap: 40px; }
  .banner { grid-template-columns: minmax(0, 1fr); gap: 32px; }
  .specs { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .profiles { grid-template-columns: minmax(0, 1fr); }
  .footer-grid { grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); }
  .site-nav { display: none; }
}
@media (max-width: 860px) {
  :root { --gutter: 22px; --section: 60px; }
  body { font-size: 17px; }
  h1 { font-size: 40px; }
  h2 { font-size: 31px; }
  h3 { font-size: 23px; }
  .lead { font-size: 19px; }
  .header-inner { min-height: 64px; gap: 16px; }
  .brand-name { font-size: 15px; max-width: 200px; }
  .header-actions { display: none; }
  .menu-toggle { display: inline-block; }
  .site-header.open .site-nav { display: grid; gap: 4px; position: absolute; left: 0; right: 0; top: 100%; background: var(--card-bg); border-bottom: 1px solid var(--line); padding: 12px var(--gutter) 20px; margin: 0; }
  .site-header.open .site-nav a { padding: 10px 0; font-size: 17px; }
  .site-header.open .header-actions { display: flex; flex-direction: column; align-items: stretch; gap: 12px; position: absolute; left: 0; right: 0; top: calc(100% + 246px); background: var(--card-bg); padding: 0 var(--gutter) 20px; border-bottom: 1px solid var(--line); }
  .hero { padding: 32px 0 48px; min-height: calc(100vh - 64px); min-height: calc(100svh - 64px); }
  .metrics { grid-template-columns: minmax(0, 1fr); gap: 16px; }
  .metrics dt { font-size: 24px; }
  .big-figure { font-size: 88px; }
  .banner-section { padding: 56px 0; }
  .photo-title { top: 16px; font-size: 30px; max-width: 70%; }
  .results { grid-template-columns: minmax(0, 1fr); gap: 20px; }
  .specs { grid-template-columns: minmax(0, 1fr); gap: 20px; }
  .features, .priorities, .app-grid, .panels { grid-template-columns: minmax(0, 1fr); }
  .profile { grid-template-columns: 120px minmax(0, 1fr); gap: 18px; }
  .profile img { width: 120px; }
  .app-feature, .app-card { padding: 22px; }
  .footer-grid { grid-template-columns: minmax(0, 1fr); gap: 28px; }
  .dialog-inner { padding: 24px; }
  dialog.form-dialog { width: 100vw; height: 100vh; max-height: 100vh; margin: 0; }
  table.compare { font-size: 15px; }
  table.compare th, table.compare td { padding: 12px 12px 12px 0; }
  .field-row { grid-template-columns: minmax(0, 1fr); }
}
@media (max-width: 420px) {
  h1 { font-size: 34px; }
  .brand-name { font-size: 14px; }
}