:root {
  --bg: black;
  --fg: white;
  --accent: rgb(128, 128, 128);
  --muted: gray;
  --shadow: rgba(255, 255, 255, 0.15);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html, body {
  height: 100%;
  font-family: 'Poppins', Arial, sans-serif;
  background: var(--bg);
  color: var(--fg);
  scroll-behavior: smooth;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.3s;
}

a:hover {
  color: var(--fg);
}

.nav-header {
  position: sticky;
  top: 0;
  background: black;
  display: flex;
  justify-content: center;
  padding: 16px 20px;
  z-index: 100;
  box-shadow: 0 4px 20px var(--shadow);
}

.nav-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
  max-width: 1200px;
}

.logo {
  height: 60px;
  filter: brightness(1.2) invert(1);
}

nav ul {
  display: flex;
  gap: 20px;
  list-style: none;
}

nav li a {
  padding: 10px 16px;
  border-radius: 8px;
  font-family: "Science Gothic", sans-serif;
  font-weight: 600;
  transition: background 0.3s;
  color: white;
}

nav li a:hover {
  background: rgba(255, 255, 255, 0.05);
}

nav .donate-btn {
  background: white;
  color: black;
  padding: 10px 18px;
  border-radius: 10px;
  font-weight: 700;
}

.nav-toggle {
  font-size: 32px;
  background: none;
  border: none;
  cursor: pointer;
  display: none;
  color: white;
}

.hero {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
  min-height: 80vh;
  padding: 60px 20px;
}

.hero h1 {
  font-size: 42px;
  font-weight: 700;
  margin-bottom: 16px;
}

.hero p {
  font-size: 18px;
  color: var(--muted);
  margin-bottom: 24px;
}

.primary-btn {
  background: var(--accent);
  color: white;
  padding: 12px 20px;
  border-radius: 10px;
  font-weight: 700;
  margin-right: 12px;
}

.secondary-btn {
  border: 2px solid var(--accent);
  color: var(--accent);
  padding: 10px 18px;
  border-radius: 10px;
}

.card-visual, .feature, .content {
  background: black;
  border-radius: 12px;
  padding: 20px;
  margin: 20px 0;
  box-shadow: 0 10px 30px var(--shadow);
  opacity: 0;
  transform: translateY(40px);
  transition: all 0.6s ease;
}

.card-visual.visible, .feature.visible, .content.visible {
  opacity: 1;
  transform: translateY(0);
}

.features {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  justify-content: center;
  max-width: 1200px;
  margin: 60px auto;
}

.feature {
  flex: 1 1 280px;
}

.page {
  max-width: 1000px;
  margin: 32px auto;
  padding: 0 20px;
}

.page-hero {
  padding: 32px 0;
}

.site-footer {
  background: black;
  text-align: center;
  padding: 20px 0 10px 0;
  color: var(--muted);
  margin-top: 40px;
  border-top: 1px solid rgba(255,255,255,0.1);
}

.site-footer p {
  margin: 4px 0;
  font-size: 14px;
}

.science-title {
  font-family: "Science Gothic", sans-serif;
  font-optical-sizing: auto;
  font-weight: 700;
  font-style: normal;
  font-variation-settings:
    "slnt" 0,
    "wdth" 112.5,
    "CTRS" 0;
}

@media(max-width: 900px) {
  nav {
    position: fixed;
    top: 0;
    right: -280px;
    width: 280px;
    height: 100%;
    background: #111;
    padding-top: 80px;
    transition: right 0.4s ease;
    z-index: 200;
  }

  nav.open {
    right: 0;
  }

  nav ul {
    flex-direction: column;
    gap: 18px;
    padding: 0;
    margin: 0;
  }

  nav ul li a {
    display: block;
    padding: 12px 20px;
    color: white;
  }

  nav .donate-btn {
    background: #ffffff;
    color: rgb(0, 0, 0);
    padding: 12px 20px;
    border-radius: 10px;
  }

  .nav-toggle {
    display: block;
  }
}