* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
body {
  font-family: 'Noto Sans JP', sans-serif;
  background: url('../img/school-img.png') center / cover fixed no-repeat;
  color: #fff;
  overflow-x: hidden;
}
body::before {
  content: "";
  position: fixed;
  top: 0; left: 0;
  width: 100%; height: 100%;
  background: rgba(0, 0, 0, 0.6);
  z-index: -1;
}
header {
  text-align: center;
  padding: 100px 20px 60px;
  animation: fadeIn 1.5s ease-in;
}
header img {
  max-width: 600px;
  width: 90%;
  filter: drop-shadow(0 0 10px #fff);
}
header h1 {
  font-size: 2rem;
  margin-top: 1rem;
  text-shadow: 0 0 8px #fff;
}
section {
  opacity: 0;
  transform: translateY(30px);
  animation: fadeUp 1s ease-out forwards;
  background-color: rgba(0, 0, 0, 0.5);
  padding: 60px 20px;
  max-width: 960px;
  margin: 40px auto;
  border-radius: 16px;
  backdrop-filter: blur(5px);
}

@keyframes fadeUp {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

h2 {
  font-size: 1.8rem;
  margin-bottom: 1rem;
  border-left: 5px solid #84b8c9;
  padding-left: 10px;
}
.cta-button {
  display: inline-block;
  background: #ffd700;
  color: #000;
  padding: 12px 24px;
  border-radius: 6px;
  text-decoration: none;
  font-weight: bold;
  margin-top: 20px;
  position: relative;
}
.cta-button::before {
  content: "";
  position: absolute;
  top: -10px; left: -10px; right: -10px; bottom: -10px;
  border: 2px solid rgba(255, 215, 0, 0.7);
  border-radius: 10px;
  animation: glow 1.5s infinite alternate;
}
@keyframes glow {
  from { opacity: 0.2; transform: scale(1); }
  to { opacity: 1; transform: scale(1.05); }
}
.teacher-card {
  background: rgba(255,255,255,0.1);
  padding: 20px;
  border-radius: 12px;
  text-align: center;
}
.teacher-card img {
  display: block;
  margin-right: auto;
  border-radius:5%;
  object-fit:cover;
  margin-bottom:10px;
}
.teacher-profile {
  display: flex;
  align-items: center;
  margin-bottom: 20px;
}
.flip-card {
  width: 100%;
  aspect-ratio: 1 / 1.3;
  perspective: 1000px;
}
.flip-card:hover .flip-card-inner {
  transform: rotateY(180deg);
}
.flip-card-inner {
  width: 100%;
  height: 100%;
  transition: transform 0.6s;
  transform-style: preserve-3d;
  position: relative;
}
.flip-card-front,
.flip-card-back {
  position: absolute;
  width: 100%;
  height: 100%;
  padding: 16px;
  border-radius: 12px;
  background: rgba(255,255,255,0.1);
  backface-visibility: hidden;
}
.flip-card-front p {
  text-align: center;
  margin-top: 10px;
  font-size: 1.1rem;
  line-height: 1.3;
  white-space: normal;
  word-break: keep-all;
  overflow-wrap: break-word;
}
.flip-card-back {
  transform: rotateY(180deg);
  text-align: center;
}
.flip-card a {
  text-decoration: none;
  color: inherit;
}
.apprentice-img {
  width: 100%;
  height: auto;
  aspect-ratio: 1 / 1;
  border-radius: 12px;
  object-fit: cover;
}
.thanks img {
  display:block;
  width: 100%;
  border-radius:10px;
}
.pv-movie iframe {
  display:block;
  width: 100%;
}
footer {
  text-align: center;
  padding: 40px 10px;
  background-color: rgba(0,0,0,0.5);
  font-size: 0.9rem;
}
.countdown {
  text-align: center;
  background: rgba(255, 215, 0, 0.15);
  border: 2px solid #ffd700;
  padding: 20px;
  margin: 40px auto;
  border-radius: 16px;
  font-size: 1.5rem;
  font-weight: bold;
  color: #fff;
  max-width: 500px;
  backdrop-filter: blur(3px);
  box-shadow: 0 0 8px rgba(255, 255, 255, 0.2);
}
.countdown  a {
  text-decoration: none;
  color: inherit;
}
.countdown span::before {
  content: " 卒業式まで あと ";
}
.countdown span::after {
  content: " 日！";
}
@media (max-width: 600px) {
  .teacher-profile {
    flex-direction: column;
    align-items: flex-start;
  }
  .teacher-profile img {
    margin-bottom: 10px;
  }
  .flip-card {
    aspect-ratio: unset;
    height: auto;
  }
  .flip-card-inner,
  .flip-card-front {
    position: relative;
    transform: none !important;
    backface-visibility: visible !important;
  }
  .flip-card-inner {
    display: flex;
    flex-direction: column;
  }
  .flip-card:hover .flip-card-inner {
    transform: none;
  }
  .inner-section {
    margin-left: 16px;
    margin-right: 16px;
  }
}