/* === VARIABLES === */
:root {
  --teal-deep:     #143E3C;
  --teal-heritage: #2F807C;
  --gold:          #ECB94C;
  --cream:         #F4ECD9;
  --charcoal:      #18201F;
  --clay:          #C8643B;

  --font-head: 'Plus Jakarta Sans', sans-serif;
  --font-body: 'Inter', sans-serif;

  --max-w: 1120px;
  --side-pad: clamp(1.25rem, 5vw, 2.5rem);
  --section-pad: clamp(4rem, 9vw, 7rem);
}

/* === RESET === */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  color: var(--charcoal);
  background: var(--cream);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

img, svg { display: block; }

/* === NAV === */
.nav {
  background: var(--teal-deep);
  position: sticky;
  top: 0;
  z-index: 100;
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}

.nav__inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 var(--side-pad);
  height: 60px;
  display: flex;
  align-items: center;
  gap: 2rem;
}

.nav__logo {
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--cream);
  text-decoration: none;
  letter-spacing: -0.01em;
  margin-right: auto;
  white-space: nowrap;
}

.nav__links {
  display: flex;
  gap: 2rem;
}

.nav__links a {
  font-family: var(--font-head);
  font-size: 0.875rem;
  font-weight: 500;
  color: rgba(244, 236, 217, 0.65);
  text-decoration: none;
  letter-spacing: 0.02em;
  transition: color 0.2s;
}

.nav__links a:hover { color: var(--cream); }

.nav__socials {
  display: flex;
  gap: 1rem;
  align-items: center;
}

.social-link {
  color: rgba(244, 236, 217, 0.55);
  transition: color 0.2s;
  display: flex;
  align-items: center;
}

.social-link:hover { color: var(--gold); }

/* === HERO === */
.hero {
  background: var(--teal-deep);
  min-height: calc(100svh - 60px);
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: var(--section-pad) var(--side-pad);
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at 72% 45%, rgba(47, 128, 124, 0.28) 0%, transparent 58%);
  pointer-events: none;
}

.hero__inner {
  max-width: var(--max-w);
  margin: 0 auto;
  width: 100%;
  position: relative;
  z-index: 1;
}

.hero__eyebrow {
  display: inline-block;
  font-family: var(--font-head);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--gold);
  margin-bottom: 1.5rem;
}

.hero__headline {
  font-family: var(--font-head);
  font-size: clamp(2.6rem, 6.5vw, 5.25rem);
  font-weight: 700;
  color: var(--cream);
  line-height: 1.06;
  letter-spacing: -0.025em;
  max-width: 14ch;
  margin-bottom: 1.5rem;
}

.hero__sub {
  font-size: clamp(1rem, 1.8vw, 1.175rem);
  color: rgba(244, 236, 217, 0.7);
  max-width: 50ch;
  line-height: 1.75;
  margin-bottom: 2.5rem;
}

.hero__scroll-hint {
  position: absolute;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  color: rgba(244, 236, 217, 0.25);
  animation: bob 2.4s ease-in-out infinite;
}

@keyframes bob {
  0%, 100% { transform: translateX(-50%) translateY(0); }
  50%       { transform: translateX(-50%) translateY(6px); }
}

/* === FOCUS === */
:focus-visible {
  outline: 2px solid var(--gold);
  outline-offset: 3px;
  border-radius: 3px;
}

/* === BUTTONS === */
.btn {
  display: inline-block;
  padding: 0.8rem 2rem;
  border-radius: 4px;
  font-family: var(--font-head);
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
  transition: background 0.2s, transform 0.15s;
  letter-spacing: 0.01em;
  cursor: pointer;
}

.btn--gold {
  background: var(--gold);
  color: var(--charcoal);
}

.btn--gold:hover {
  background: #d9a53e;
  transform: translateY(-1px);
}

/* === SECTION SHELL === */
.section {
  padding: var(--section-pad) var(--side-pad);
  background: var(--cream);
}

.section--tint { background: #ede6d2; }

.container {
  max-width: var(--max-w);
  margin: 0 auto;
}

.section__header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1.5rem;
  margin-bottom: 3rem;
}

.section__title {
  font-family: var(--font-head);
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  font-weight: 700;
  color: var(--charcoal);
  letter-spacing: -0.02em;
  line-height: 1.1;
}

/* === FILTER BAR === */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: center;
}

.filter-btn {
  font-family: var(--font-head);
  font-size: 0.78rem;
  font-weight: 500;
  letter-spacing: 0.03em;
  padding: 0.4rem 1rem;
  border-radius: 100px;
  border: 1.5px solid rgba(20, 62, 60, 0.2);
  background: transparent;
  color: rgba(24, 32, 31, 0.6);
  cursor: pointer;
  transition: all 0.18s;
}

.filter-btn:hover {
  border-color: var(--teal-heritage);
  color: var(--teal-heritage);
}

.filter-btn.active {
  background: var(--teal-deep);
  border-color: var(--teal-deep);
  color: var(--cream);
}

/* === VIDEO GRID === */
.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.75rem;
}

.video-card {
  background: #fff;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 1px 4px rgba(20, 62, 60, 0.07);
  transition: transform 0.22s, box-shadow 0.22s;
  cursor: pointer;
}

.video-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 10px 28px rgba(20, 62, 60, 0.13);
}

/* thumbnail placeholders */
.video-card__thumb {
  aspect-ratio: 16 / 9;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}

.thumb--teal      { background: var(--teal-heritage); }
.thumb--teal-dark { background: var(--teal-deep); }
.thumb--heritage  { background: #1c5250; }
.thumb--clay      { background: var(--clay); }
.thumb--clay-dark { background: #9e4e2a; }
.thumb--gold      { background: #c49030; }

.thumb__play {
  width: 46px;
  height: 46px;
  border-radius: 50%;
  border: 2px solid rgba(255, 255, 255, 0.45);
  background: rgba(255, 255, 255, 0.12);
  display: flex;
  align-items: center;
  justify-content: center;
  color: rgba(255, 255, 255, 0.85);
  font-size: 0.9rem;
  padding-left: 3px;
  transition: all 0.2s;
  backdrop-filter: blur(4px);
}

.video-card:hover .thumb__play {
  background: rgba(255, 255, 255, 0.22);
  border-color: rgba(255, 255, 255, 0.75);
  transform: scale(1.1);
}

.video-card__body {
  padding: 1rem 1.25rem 1.4rem;
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
}

/* === TAGS === */
.tag {
  font-family: var(--font-head);
  font-size: 0.68rem;
  font-weight: 600;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  padding: 0.2rem 0.55rem;
  border-radius: 3px;
  display: inline-block;
  width: fit-content;
}

.tag--history    { background: rgba(200, 100, 59, 0.12); color: #8a3d1c; }
.tag--science    { background: rgba(47, 128, 124, 0.12); color: var(--teal-deep); }
.tag--systems    { background: rgba(20, 62, 60, 0.1);   color: var(--teal-deep); }
.tag--economics  { background: rgba(236, 185, 76, 0.22); color: #7a5c12; }
.tag--technology { background: rgba(47, 128, 124, 0.12); color: var(--teal-deep); }

.video-card__title {
  font-family: var(--font-head);
  font-size: 1rem;
  font-weight: 600;
  color: var(--charcoal);
  line-height: 1.35;
  letter-spacing: -0.01em;
}

.video-card__meta {
  font-size: 0.78rem;
  color: rgba(24, 32, 31, 0.58);
  margin-top: 0.2rem;
}

.video-grid__empty {
  font-family: var(--font-head);
  font-size: 0.95rem;
  color: rgba(24, 32, 31, 0.4);
  padding: 2rem 0;
  text-align: center;
  grid-column: 1 / -1;
}

/* === ABOUT === */
.about {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 5rem;
  align-items: center;
}

.about .section__title { margin-bottom: 1.5rem; }

.about__lead {
  font-family: var(--font-head);
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--charcoal);
  line-height: 1.45;
  letter-spacing: -0.01em;
  margin-bottom: 1.25rem;
}

.about__body p {
  font-size: 1rem;
  color: rgba(24, 32, 31, 0.78);
  line-height: 1.8;
  margin-bottom: 1rem;
}

.about__body p:last-child { margin-bottom: 0; }

.about__body em {
  font-style: italic;
  color: var(--charcoal);
}

.about__pull {
  border-left: 3px solid var(--gold);
  padding: 1.75rem 2rem;
  background: rgba(236, 185, 76, 0.07);
  border-radius: 0 8px 8px 0;
}

.about__pull p {
  font-family: var(--font-head);
  font-size: clamp(1.15rem, 2vw, 1.45rem);
  font-weight: 600;
  color: var(--teal-deep);
  line-height: 1.5;
  letter-spacing: -0.01em;
}

/* === FOOTER === */
.footer {
  background: var(--teal-deep);
  padding: 3rem var(--side-pad);
  border-top: 1px solid rgba(255, 255, 255, 0.06);
}

.footer__inner {
  max-width: var(--max-w);
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 0.6rem;
}

.footer__logo {
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--cream);
  letter-spacing: -0.01em;
}

.footer__tagline {
  font-size: 0.875rem;
  color: rgba(244, 236, 217, 0.60);
}

.footer__socials {
  display: flex;
  gap: 1.25rem;
  margin-top: 0.75rem;
}

/* === RESPONSIVE === */
@media (max-width: 760px) {
  .nav__links { display: none; }

  .section__header { flex-direction: column; }

  .about {
    grid-template-columns: 1fr;
    gap: 2.5rem;
  }

  .about__pull { padding: 1.25rem 1.5rem; }
}

@media (max-width: 480px) {
  .video-grid { grid-template-columns: 1fr; }
}