:root {
  --bg: #f3f6fb;
  --card: #ffffff;
  --text: #1d2735;
  --muted: #5c6c80;
  --accent: #0b4f9c;
  --accent-soft: #dceafb;
  --border: #d7e0ec;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Avenir Next", "Segoe UI", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at 5% 5%, #ffffff 0, #eef4fc 35%, transparent 55%),
    radial-gradient(circle at 95% 0%, #e0edff 0, #f3f6fb 40%, transparent 60%),
    var(--bg);
  line-height: 1.5;
}

.hero {
  text-align: center;
  padding: 2.75rem 1rem 1.5rem;
}

.hero-mark {
  width: 96px;
  height: auto;
}

h1,
h2 {
  margin: 0;
  line-height: 1.2;
}

h1 {
  margin-top: 0.5rem;
  font-size: clamp(1.8rem, 4vw, 2.6rem);
}

h2 {
  margin-bottom: 0.7rem;
  font-size: clamp(1.25rem, 2.5vw, 1.5rem);
}

.hero-subtitle {
  margin: 0.6rem auto 0;
  max-width: 680px;
  color: var(--muted);
}

.container {
  max-width: 1024px;
  margin: 0 auto;
  padding: 0 1rem 2rem;
}

.feature-card {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 1rem;
  box-shadow: 0 10px 26px rgba(30, 61, 109, 0.08);
  margin-bottom: 1.4rem;
}

.feature-card img {
  width: 100%;
  border-radius: 12px;
  max-height: 320px;
  object-fit: cover;
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 0.75rem;
}

.grid-compact {
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.card-link {
  display: block;
  text-decoration: none;
  color: var(--text);
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 0.8rem 0.95rem;
  font-weight: 600;
  transition: transform 0.12s ease, box-shadow 0.12s ease, border-color 0.12s ease;
}

.card-link:hover,
.card-link:focus-visible {
  transform: translateY(-1px);
  box-shadow: 0 8px 20px rgba(11, 79, 156, 0.13);
  border-color: var(--accent);
  outline: none;
}

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

.youtube-link {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  margin-top: 0.45rem;
  padding: 0.62rem 1.05rem;
  border-radius: 12px;
  text-decoration: none;
  color: #fff;
  font-weight: 700;
  background: #ff0000;
  border: 1px solid #d40000;
  box-shadow: 0 10px 22px rgba(153, 0, 0, 0.28);
  transition: transform 0.12s ease, box-shadow 0.12s ease, background-color 0.12s ease;
}

.youtube-link:hover,
.youtube-link:focus-visible {
  transform: translateY(-1px);
  background: #e60000;
  box-shadow: 0 14px 28px rgba(153, 0, 0, 0.34);
  outline: none;
}

.youtube-logo {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  background: #ffffff;
  color: #111111;
  border-radius: 999px;
  padding: 0.18rem 0.52rem 0.18rem 0.28rem;
  line-height: 1;
}

.youtube-play {
  width: 1.28rem;
  height: 0.9rem;
  border-radius: 0.25rem;
  background: #ff0000;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.youtube-play::before {
  content: "";
  display: block;
  width: 0;
  height: 0;
  border-top: 0.2rem solid transparent;
  border-bottom: 0.2rem solid transparent;
  border-left: 0.34rem solid #ffffff;
  margin-left: 0.05rem;
}

.youtube-word {
  font-size: 0.82rem;
  font-weight: 800;
}

.youtube-text {
  font-size: 0.95rem;
}

.site-footer {
  text-align: center;
  color: var(--muted);
  padding: 1rem;
}

@media (min-width: 760px) {
  .feature-card {
    grid-template-columns: 1.1fr 1fr;
    align-items: center;
    padding: 1.2rem;
  }
}