#nav-btn, .nav-btn {
  display: inline-block;
  background: #0984e3;
  color: #fff;
  padding: 8px 24px;
  border-radius: 8px;
  text-decoration: none;
  font-weight: bold;
  font-size: 1rem;
  margin: 0 8px;
  box-shadow: 0 1px 4px rgba(0,0,0,0.04);
  transition: background 0.2s, color 0.2s;
}
#nav-btn:hover, .nav-btn:hover {
  background: #74b9ff;
  color: #fff;
}
#save-student-number {
  accent-color: #0984e3;
  width: 20px;
  height: 20px;
  vertical-align: middle;
}
.save-label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 1rem;
  color: #636e72;
  background: #f5f6fa;
  border-radius: 8px;
  padding: 6px 16px;
  margin-bottom: 12px;
  box-shadow: 0 1px 4px rgba(0,0,0,0.04);
}
body {
  font-family: 'Segoe UI', 'Meiryo', 'sans-serif';
  background: #f5f6fa;
  margin: 0;
  padding: 0;
}

h1 {
  text-align: center;
  color: #00bfff;
  font-weight: bold;
  margin-top: 32px;
  font-size: 2.2rem;
  letter-spacing: 0.05em;
  position: relative;
  padding-bottom: 18px;
}
h1::after {
  content: '';
  display: block;
  width: 60%;
  height: 6px;
  margin: 0 auto;
  border-radius: 3px;
  background: linear-gradient(90deg, #00bfff 0%, #74b9ff 50%, #00b894 100%);
  position: absolute;
  left: 20%;
  bottom: 0;
}

p {
  text-align: center;
  color: #636e72;
}

#student-number {
  display: block;
  margin: 16px auto 8px auto;
  padding: 8px;
  border-radius: 8px;
  border: 1px solid #b2bec3;
  width: 120px;
  font-size: 1rem;
}

#submit-button {
  display: block;
  margin: 0 auto 24px auto;
  padding: 10px 32px;
  background: #0984e3;
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  cursor: pointer;
  transition: background 0.2s;
}
#submit-button:disabled {
  background: #b2bec3;
  cursor: not-allowed;
}
#submit-button:hover:not(:disabled) {
  background: #74b9ff;
}

#list {
  display: flex;
  justify-content: center;
  gap: 12px;
  margin-bottom: 24px;
}
#list a {
  display: inline-block;
  background: #dfe6e9;
  color: #636e72;
  padding: 8px 16px;
  border-radius: 6px;
  text-decoration: none;
  font-weight: bold;
  transition: background 0.2s, color 0.2s;
}
#list a:hover {
  background: #0984e3;
  color: #fff;
}

.result {
  max-width: 400px;
  margin: 32px auto;
  background: #fff;
  border-radius: 12px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.07);
  padding: 24px;
}
.result.active {
  display: block;
}
.result h2 {
  text-align: center;
  color: #0984e3;
  margin-bottom: 16px;
}
.result table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 16px;
}
.result th, .result td {
  padding: 8px;
  text-align: left;
}
.result th {
  background: #dfe6e9;
  color: #636e72;
  border-radius: 4px;
}
.result td {
  background: #f5f6fa;
  border-radius: 4px;
}
.result input[type="number"] {
  width: 60px;
  padding: 6px;
  border-radius: 6px;
  border: 1px solid #b2bec3;
  font-size: 1rem;
}
.result button {
  display: block;
  margin: 0 auto;
  padding: 8px 24px;
  background: #00b894;
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  cursor: pointer;
  transition: background 0.2s;
}
.result button:hover {
  background: #55efc4;
}
.result p {
  display: inline;
  margin-left: 4px;
  color: #636e72;
  font-size: 0.95rem;
}

@media (max-width: 600px) {
  .result {
    max-width: 98vw;
    padding: 8px;
  }
  #list {
    flex-wrap: wrap;
    gap: 6px;
  }
}