body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI",
               "Helvetica Neue", "Yu Gothic", "ヒラギノ角ゴ ProN",
               sans-serif;
  margin: 0;
  padding: 0;
  background: #f5f7fa;
  color: #333;
  font-size: 15px;
}

.container {
  max-width: 720px;
  margin: 32px auto;
  padding: 0 16px;
  box-sizing: border-box;
}

header {
  background: #fff;
  padding: 16px 20px;
  border-radius: 8px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.06);
  position: relative;
}
header h1 {
  margin: 0;
  font-size: 1.3rem;
  line-height: 1.5;
}
header a {
  position: absolute;
  right: 20px;
  top: 18px;
  font-size: 0.9rem;
  text-decoration: none;
  color: #007bff;
}
header a:hover {
  text-decoration: underline;
}

form {
  margin-top: 24px;
  padding: 20px;
  background: #fff;
  border-radius: 8px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.06);
}

p {
  margin-top: 0;
  margin-bottom: 16px;
}

.form-group {
  margin-bottom: 16px;
}
.form-group label {
  display: block;
  font-weight: 600;
  margin-bottom: 4px;
}

.form-control {
  width: 100%;
  padding: 8px 10px;
  font-size: 1rem;
  border: 1px solid #ccc;
  border-radius: 4px;
  box-sizing: border-box;
}
.form-control:focus {
  border-color: #007bff;
  outline: none;
  box-shadow: 0 0 0 2px rgba(0,123,255,0.15);
}

.badge-danger {
  display: inline-block;
  margin-left: 4px;
  padding: 2px 6px;
  font-size: 0.75rem;
  color: #fff;
  background: #dc3545;
  border-radius: 10px;
}

.input-group {
  display: flex;
  gap: 8px;
}
.input-group .form-control {
  flex: 1;
}

.btn-area {
  margin-top: 8px;
}

.btn {
  display: inline-block;
  padding: 8px 18px;
  font-size: 0.95rem;
  border-radius: 4px;
  border: none;
  cursor: pointer;
  margin-right: 8px;
}
.btn-primary {
  background: #007bff;
  color: #fff;
}
.btn-primary:hover {
  background: #0069d9;
}
.btn-secondary {
  background: #6c757d;
  color: #fff;
}
.btn-secondary:hover {
  background: #5a6268;
}
.btn-outline {
  background: #fff;
  color: #555;
  border: 1px solid #ccc;
}
.btn-outline:hover {
  background: #f0f0f0;
}

footer {
  margin-top: 20px;
  text-align: center;
  font-size: 0.85rem;
  color: #777;
}

/* --- スマホ向け調整 --- */
@media (max-width: 600px) {
  .input-group {
    flex-direction: column;
    align-items: stretch;
  }
  .btn {
    width: 100%;
    margin-right: 0;
    margin-bottom: 8px;
  }
}

/* --- PC向け（横幅が広いとき）の余白調整 --- */
@media (min-width: 900px) {
  .container {
    margin-top: 48px;
  }
  form {
    padding: 24px 28px;
  }
}

.error-box {
  margin-top: 24px;
  padding: 16px 20px;
  border-radius: 6px;
  background: #fff5f5;
  border: 1px solid #f5c2c7;
  color: #842029;
}
.error-title {
  margin: 0 0 8px;
  font-weight: 700;
}
.error-actions {
  margin-top: 16px;
}