* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans TC", sans-serif;
  background: #f5f6f8;
  color: #202124;
}

.page {
  min-height: 100vh;
  padding: 24px 16px;
}

.card {
  width: 100%;
  max-width: 640px;
  margin: 0 auto;
  background: #fff;
  border-radius: 18px;
  padding: 28px 22px;
  box-shadow: 0 8px 30px rgba(0,0,0,.08);
}

.brand {
  font-size: 14px;
  font-weight: 700;
  color: #6b7280;
  margin-bottom: 8px;
}

h1 {
  margin: 0 0 10px;
  font-size: 30px;
}

.intro {
  margin: 0 0 26px;
  color: #6b7280;
  line-height: 1.6;
}

form {
  display: grid;
  gap: 18px;
}

label {
  display: grid;
  gap: 8px;
  font-weight: 700;
  font-size: 15px;
}

input,
select,
textarea {
  width: 100%;
  border: 1px solid #d8dce3;
  border-radius: 10px;
  padding: 13px 14px;
  font: inherit;
  background: #fff;
}

textarea {
  resize: vertical;
}

.grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
}

button {
  border: 0;
  border-radius: 12px;
  padding: 14px;
  font-size: 16px;
  font-weight: 800;
  cursor: pointer;
  background: #111827;
  color: white;
}

button:disabled {
  opacity: .6;
  cursor: wait;
}

.message {
  min-height: 24px;
  text-align: center;
  font-weight: 700;
}

.message.ok {
  color: #15803d;
}

.message.error {
  color: #b91c1c;
}

@media (max-width: 520px) {
  .grid {
    grid-template-columns: 1fr;
  }

  .card {
    padding: 22px 16px;
    border-radius: 14px;
  }

  h1 {
    font-size: 26px;
  }
}