/*
  Kimura Laboratory - course-only pages
  CSS3 / JavaScriptなし
*/

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

html {
  font-size: 16px;
}

body {
  min-height: 100vh;
  font-family: "Yu Gothic UI", "Yu Gothic", Meiryo, sans-serif;
  line-height: 1.8;
  color: #263238;
  background: #eef6fb;
}

.site-header {
  position: relative;
  overflow: hidden;
  color: #fff;
  text-align: center;
  background: linear-gradient(135deg, #0d47a1 0%, #1565c0 45%, #00bcd4 100%);
  padding: 58px 20px 52px;
}

.site-header::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image: radial-gradient(rgba(255,255,255,.16) 1px, transparent 1px);
  background-size: 28px 28px;
  opacity: .45;
}

.header-inner {
  position: relative;
  z-index: 1;
  max-width: 980px;
  margin: 0 auto;
}

.eyebrow {
  letter-spacing: .16em;
  text-transform: uppercase;
  font-size: .86rem;
  opacity: .9;
}

.site-header h1 {
  margin-top: 8px;
  font-size: clamp(2rem, 5vw, 3rem);
  letter-spacing: .06em;
}

.lab-name {
  margin-top: 8px;
  font-size: clamp(1.15rem, 3vw, 1.65rem);
  font-weight: 300;
}

main {
  max-width: 760px;
  margin: 48px auto 0;
  padding: 0 20px;
}

.section-title {
  margin-bottom: 20px;
  padding-left: 14px;
  border-left: 7px solid #00bcd4;
  color: #0d47a1;
  font-size: clamp(1.4rem, 3vw, 1.8rem);
}

.lecture-card {
  overflow: hidden;
  background: #fff;
  border-radius: 18px;
  box-shadow: 0 8px 24px rgba(13,71,161,.10);
  transition: transform .25s ease, box-shadow .25s ease;
}

.lecture-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 18px 40px rgba(13,71,161,.18);
}

.card-header {
  min-height: 190px;
  padding: 36px 22px;
  color: #fff;
  text-align: center;
  background: linear-gradient(135deg, #1565c0 0%, #00bcd4 100%);
}

.label {
  display: inline-block;
  margin-bottom: 18px;
  padding: 4px 12px;
  border: 1px solid rgba(255,255,255,.62);
  border-radius: 999px;
  font-size: .68rem;
  font-weight: 700;
  letter-spacing: .14em;
}

.card-header h2 {
  font-size: clamp(1.5rem, 4vw, 2rem);
}

.card-header p {
  margin-top: 6px;
  opacity: .92;
}

.card-body {
  padding: 26px;
}

.description {
  color: #455a64;
}

.button-row {
  display: flex;
  gap: 10px;
  margin-top: 24px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 50px;
  border-radius: 10px;
  font-weight: 700;
  line-height: 1;
  text-decoration: none;
  white-space: nowrap;
  transition: transform .2s ease, background-color .2s ease, border-color .2s ease, color .2s ease;
}

.play-button {
  flex: 1 1 auto;
  background: #1565c0;
  color: #fff;
}

.play-button:hover {
  background: #0d47a1;
  transform: translateY(-2px);
}

.pdf-button {
  flex: 0 0 90px;
  border: 2px solid #d32f2f;
  background: #fff;
  color: #d32f2f;
}

.pdf-button:hover {
  border-color: #b71c1c;
  background: #ffebee;
  color: #b71c1c;
  transform: translateY(-2px);
}

.notice {
  margin-top: 18px;
  color: #607d8b;
  font-size: .9rem;
  text-align: center;
}

.site-footer {
  margin-top: 64px;
  padding: 28px 20px;
  color: #fff;
  text-align: center;
  background: #0d47a1;
}

.site-footer h2 {
  font-size: 1.1rem;
  letter-spacing: .08em;
}

.site-footer p {
  margin-top: 6px;
  font-size: .86rem;
  opacity: .9;
}

@media (max-width: 640px) {
  .site-header {
    padding: 44px 18px;
  }

  main {
    margin-top: 32px;
    padding: 0 16px;
  }

  .button-row {
    gap: 8px;
  }

  .pdf-button {
    flex-basis: 76px;
  }
}