* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: #f3f6ff;
  color: #111827;
  animation: slide-in 0.6s ease-out;
}

@keyframes slide-in {
  from {
    opacity: 0;
    transform: translateY(40px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.page {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-start;
  padding: 32px 16px 40px;
}

.hero {
  text-align: center;
  margin-bottom: 32px;
}

.hero-image {
  width: 150px;
  max-width: 50vw;
  display: block;
  margin: 0 auto 16px;
}

h1 {
  font-size: clamp(1.7rem, 2.2vw + 1rem, 2.2rem);
  margin: 0;
}

.subtitle {
  margin-top: 8px;
  font-size: 0.95rem;
  color: #4b5563;
}

.button-list {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 18px;
}

.concept-btn,
.back-btn {
  display: inline-block;
  min-width: 220px;
  padding: 10px 32px;
  border-radius: 12px;
  background: #c4ddff;
  border: 3px solid #000000;
  text-decoration: none;
  color: #111827;
  font-weight: 600;
  text-align: center;
  box-shadow: 0 5px 0 #0f172a;
  transition: transform 0.15s ease, box-shadow 0.15s ease, background 0.15s ease;
}

.concept-btn:hover,
.back-btn:hover {
  transform: translateY(-2px) scale(1.03);
  box-shadow: 0 8px 16px rgba(15, 23, 42, 0.4);
  background: #d6e7ff;
}

.content {
  max-width: 680px;
  width: 100%;
}

.placeholder {
  background: #ffffff;
  border-radius: 16px;
  padding: 20px 18px;
  border: 1px solid #e5e7eb;
  box-shadow: 0 10px 25px rgba(15, 23, 42, 0.08);
  line-height: 1.6;
  font-size: 0.98rem;
}

.footer {
  margin-top: 32px;
}

@media (max-width: 480px) {
  .concept-btn,
  .back-btn {
    min-width: 70vw;
    padding-inline: 20px;
  }
}