body {
  font-family: 'Noto Sans JP', sans-serif;
  margin: 0;
  color: #333;
  background: #fdfdfd;
  line-height: 1.8;
}

/* Hero Header */
.hero {
  background: linear-gradient(120deg, #02ccba, #4588b5);
  color: white;
  text-align: center;
  padding: 100px 20px 80px;
}

.hero-content h1 {
  font-size: 2.5em;
  margin-bottom: 10px;
}

.hero-content p {
  font-size: 1.2em;
  opacity: 0.9;
}

/* General Section */
main {
  padding: 60px 20px;
}

section {
  max-width: 900px;
  margin: 0 auto 70px;
  background: white;
  border-radius: 12px;
  box-shadow: 0 4px 10px rgba(0,0,0,0.08);
  padding: 40px;
  text-align: center;
}

section h2 {
  font-size: 1.7em;
  color: #02ccba;
  margin-bottom: 25px;
}

/* Equipment */
.equip-list {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 15px;
  margin-bottom: 30px;
}

.equip-item {
  background: #02ccba;
  color: white;
  padding: 14px 20px;
  border-radius: 25px;
  font-weight: bold;
  box-shadow: 0 3px 8px rgba(0,0,0,0.2);
}

.lang {
  background: #132d32;
  color: white;
  padding: 6px 12px;
  border-radius: 6px;
  font-weight: bold;
}

/* Diagram */
.diagram-img {
  width: 90%;
  max-width: 700px;
  border-radius: 8px;
  margin: 20px 0;
  box-shadow: 0 4px 15px rgba(0,0,0,0.1);
  transition: transform 0.3s ease;
}

.diagram-img:hover {
  transform: scale(1.03);
}

/* Background Section */
.background p {
  color: #444;
  text-align: left;
  line-height: 1.9;
  max-width: 800px;
  margin: 0 auto;
}

/* Demo */
.video-wrapper {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 25px;
}

iframe {
  border-radius: 10px;
  box-shadow: 0 4px 15px rgba(0,0,0,0.15);
}

/* Back Button */
.back-container {
  text-align: center;
  margin-top: 40px;
}

.back-button {
  display: inline-block;
  background: #02ccba;
  color: white;
  padding: 12px 24px;
  border-radius: 25px;
  text-decoration: none;
  font-weight: bold;
  box-shadow: 0 3px 10px rgba(0,0,0,0.2);
  transition: background 0.3s ease, transform 0.3s ease;
}

.back-button:hover {
  background: #4588b5;
  transform: translateY(-3px);
}

/* Footer */
footer {
  text-align: center;
  padding: 20px;
  background: #132d32;
  color: white;
  font-size: 0.9em;
}