:root {
  --color-bg: #fafaf7;
  --color-fg: #1a1a1a;
  --color-muted: #6b6b6b;
  --color-accent: #2c5d3f;
  --color-border: #e2e2dc;
  --color-card-bg: #ffffff;
  --color-card-shadow: 0 1px 3px rgba(0, 0, 0, 0.06), 0 4px 12px rgba(0, 0, 0, 0.04);
  --color-card-shadow-hover: 0 2px 6px rgba(0, 0, 0, 0.08), 0 8px 24px rgba(0, 0, 0, 0.08);

  --font-body: -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", Helvetica, Arial, sans-serif;
  --font-display: "Iowan Old Style", "Palatino Linotype", Palatino, "Book Antiqua", Georgia, serif;

  --content-max-width: 64rem;
  --gap-sm: 0.5rem;
  --gap-md: 1rem;
  --gap-lg: 2rem;
  --gap-xl: 3rem;
}

* {
  box-sizing: border-box;
}

html {
  font-size: 16px;
}

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.55;
  color: var(--color-fg);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3 {
  font-family: var(--font-display);
  font-weight: 600;
  line-height: 1.2;
  margin: 0 0 0.5em;
}

h1 { font-size: 2.25rem; }
h2 { font-size: 1.5rem; }
h3 { font-size: 1.15rem; }

p {
  margin: 0 0 1em;
}

a {
  color: var(--color-accent);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.15s ease;
}

a:hover {
  border-bottom-color: var(--color-accent);
}

.site-header {
  border-bottom: 1px solid var(--color-border);
  padding: 1rem 1.5rem;
  background: var(--color-card-bg);
}

.site-header__inner {
  max-width: var(--content-max-width);
  margin: 0 auto;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--gap-md);
}

.site-header__brand {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--color-fg);
  border: none;
}

.site-header__nav {
  font-size: 0.9rem;
  color: var(--color-muted);
}

.site-main {
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: var(--gap-xl) 1.5rem;
}

.site-footer {
  max-width: var(--content-max-width);
  margin: var(--gap-xl) auto 0;
  padding: var(--gap-lg) 1.5rem;
  border-top: 1px solid var(--color-border);
  font-size: 0.85rem;
  color: var(--color-muted);
}

.lede {
  font-size: 1.1rem;
  color: var(--color-muted);
}

/* ================ Presentation block (umbrella page) ================ */

.presentation {
  margin-top: var(--gap-xl);
  margin-bottom: var(--gap-xl);
}

.presentation__title {
  margin-top: 0;
}

.presentation__intro {
  color: var(--color-muted);
}

.presentation__video {
  /* 53.6% padding-top reproduces Vimeo's "padding:53.6% 0 0 0" wrapper —
     a slightly-wider-than-16:9 aspect (1.866:1) that matches the recorded
     video's actual dimensions. iframe absolute-positioned to fill. */
  position: relative;
  padding-top: 53.6%;
  margin: var(--gap-md) 0;
  background: #000;
  border-radius: 6px;
  overflow: hidden;
}

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

.presentation__downloads {
  margin-top: var(--gap-md);
  margin-bottom: 0;
  display: flex;
  flex-wrap: wrap;
  gap: var(--gap-sm);
}

.presentation__download-link {
  display: inline-block;
  padding: 0.6rem 1rem;
  background: var(--color-card-bg);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  font-weight: 600;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.presentation__download-link:hover {
  border-color: var(--color-accent);
  box-shadow: var(--color-card-shadow);
}

/* ================ Umbrella project list ================ */

.project-list {
  display: grid;
  gap: var(--gap-lg);
  margin-top: var(--gap-xl);
  grid-template-columns: 1fr;
}

@media (min-width: 48rem) {
  .project-list {
    grid-template-columns: repeat(2, 1fr);
  }
}

.project-card {
  display: block;
  padding: var(--gap-lg);
  background: var(--color-card-bg);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  box-shadow: var(--color-card-shadow);
  color: inherit;
  transition: box-shadow 0.2s ease, transform 0.2s ease, border-color 0.2s ease;
}

.project-card:hover {
  box-shadow: var(--color-card-shadow-hover);
  transform: translateY(-2px);
  border-color: var(--color-accent);
}

.project-card__title {
  margin-top: 0;
}

.project-card__body {
  color: var(--color-muted);
  margin-bottom: 0.75em;
}

.project-card__cta {
  font-weight: 600;
  color: var(--color-accent);
  font-size: 0.95rem;
}