/* ---------------------------------------------------------
   Simple, lightweight stylesheet — no external fonts, no
   frameworks, no build step. Keeps the page fast-loading
   and low-carbon to serve.
--------------------------------------------------------- */

:root {
  --text: #1f2a24;
  --bg: #ffffff;
  --bg-alt: #f2f6f3;
  --accent: #2f6b4f;   /* deep green — change to suit your branding */
  --accent-dark: #1f4a36;
  --title-pink: #c71585;
  --max-width: 780px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.25rem;
}

/* Header */
.site-header {
  border-bottom: 1px solid #e2e8e4;
  position: sticky;
  top: 0;
  background: var(--bg);
  z-index: 10;
}

.header-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  padding: 0.9rem 1.25rem;
}

.site-title {
  font-weight: 700;
  margin: 0;
  color: var(--accent-dark);
}

.site-header nav a {
  margin-left: 1.25rem;
  text-decoration: none;
  color: var(--text);
  font-size: 0.95rem;
}

.site-header nav a:hover { color: var(--accent); }

/* Banner */
.banner {
  background: var(--bg);
}

.banner-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding-top: 1rem;
  padding-bottom: 1rem;
}

.imperial-logo {
  display: block;
  width: min(220px, 52vw);
  height: auto;
}

.dept-name {
  color: #5c6c62;
  font-size: 0.95rem;
  text-align: right;
}

.banner-pink {
  padding-bottom: 1.5rem;
}

.banner-pink-inner {
  display: flex;
  flex-direction: column;
  align-items: stretch;
}

.banner-title {
  display: block;
  margin: 0;
  padding: 0.8rem 1rem;
  background: var(--title-pink);
  color: #fff;
  line-height: 1.18;
}

.site-nav {
  border-top: 1px solid #e2e8e4;
  border-bottom: 1px solid #e2e8e4;
}

.site-nav .container {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem 1.5rem;
  padding-top: 0.85rem;
  padding-bottom: 0.85rem;
}

.site-nav a {
  color: var(--text);
  font-size: 0.95rem;
  font-weight: 600;
  text-decoration: none;
}

.site-nav a:hover {
  color: var(--accent);
}

/* Hero */
.hero {
  padding: 3.5rem 0 2.5rem;
  background: var(--bg-alt);
}

.hero h1 {
  margin: 0 0 0.5rem;
  font-size: 2rem;
  color: var(--accent-dark);
}

.tagline {
  font-size: 1.15rem;
  margin: 0;
  color: #445048;
}

/* Sections */
.section { padding: 3rem 0; }
.section.alt { background: var(--bg-alt); }

.section h2 {
  margin-top: 0;
  color: var(--accent-dark);
  font-size: 1.5rem;
}

.section ul {
  padding-left: 1.25rem;
}

.section li { margin-bottom: 0.4rem; }

.project-details {
  margin-top: 1.5rem;
}

/* Buttons */
.button {
  display: inline-block;
  background: var(--accent);
  color: #fff;
  padding: 0.65rem 1.3rem;
  border-radius: 6px;
  text-decoration: none;
  font-weight: 600;
}

.button:hover { background: var(--accent-dark); }

/* Video embed — keeps a responsive 16:9 ratio */
.video-wrapper {
  position: relative;
  width: 100%;
  margin-top: 1.5rem;
  padding-top: 56.25%;
  background: #000;
  border-radius: 6px;
  overflow: hidden;
}

.video-wrapper iframe {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
  border: 0;
}

/* Footer */
.site-footer {
  padding: 1.5rem 0;
  font-size: 0.85rem;
  color: #6b7a71;
  text-align: center;
  border-top: 1px solid #e2e8e4;
}

/* Small screens */
@media (max-width: 600px) {
  .banner-top { align-items: flex-start; flex-direction: column; }
  .dept-name { text-align: left; }
  .header-inner { flex-direction: column; align-items: flex-start; }
  .site-header nav { margin-top: 0.5rem; }
  .site-header nav a { margin-left: 0; margin-right: 1rem; }
  .hero h1 { font-size: 1.6rem; }
}