:root {
  --bg: #eef4f1;
  --card: #ffffff;
  --ink: #142033;
  --muted: #66758a;
  --line: #d7e0e7;
  --accent: #087a63;
  --accent-dark: #045944;
  --accent-soft: #e2f5ef;
  --danger: #b42318;
  --shadow: 0 24px 70px rgba(20, 32, 51, 0.12);
}

* {
  box-sizing: border-box;
}

body {
  min-height: 100vh;
  margin: 0;
  color: var(--ink);
  font-family: "Microsoft YaHei", "PingFang SC", "Noto Sans CJK SC", sans-serif;
  background:
    radial-gradient(circle at 10% 8%, rgba(8, 122, 99, 0.14), transparent 30%),
    linear-gradient(135deg, #f7faf9, var(--bg));
}

button,
input {
  font: inherit;
}

.app {
  width: min(100% - 28px, 760px);
  margin: 0 auto;
  padding: 36px 0;
}

.card {
  display: grid;
  gap: 22px;
  padding: 34px;
  border: 1px solid rgba(215, 224, 231, 0.9);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.94);
  box-shadow: var(--shadow);
}

.header {
  display: grid;
  gap: 10px;
  text-align: center;
}

.tag,
h1,
h2,
p {
  margin: 0;
}

.tag {
  color: var(--accent-dark);
  font-size: 0.78rem;
  font-weight: 800;
  text-transform: uppercase;
}

h1 {
  font-size: clamp(2rem, 5vw, 3rem);
  line-height: 1.08;
}

h2 {
  font-size: 1.2rem;
}

.summary,
.hint,
.message {
  color: var(--muted);
  line-height: 1.7;
}

.status {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  padding: 14px 16px;
  border-radius: 10px;
}

.status {
  border: 1px solid var(--line);
  background: #f8fbfa;
}

.form {
  display: grid;
  gap: 10px;
}

.label {
  font-weight: 800;
}

.input-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 86px;
  gap: 10px;
}

input {
  width: 100%;
  min-height: 56px;
  padding: 0 16px;
  border: 1px solid var(--line);
  border-radius: 10px;
  color: var(--ink);
  background: #fff;
}

input:focus {
  outline: 3px solid rgba(8, 122, 99, 0.16);
  border-color: var(--accent);
}

.primary-button,
.secondary-button {
  min-height: 50px;
  border: 0;
  border-radius: 10px;
  color: #fff;
  background: var(--accent);
  font-weight: 800;
  cursor: pointer;
}

.primary-button:hover:not(:disabled),
.secondary-button:hover {
  background: var(--accent-dark);
}

.primary-button:disabled {
  cursor: not-allowed;
  opacity: 0.5;
}

.result {
  display: grid;
  gap: 16px;
  padding: 20px;
  border: 1px solid rgba(8, 122, 99, 0.2);
  border-radius: 12px;
  background: var(--accent-soft);
}

.code {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 104px;
  border-radius: 12px;
  color: var(--accent-dark);
  background: #fff;
  font-family: Consolas, "SFMono-Regular", monospace;
  font-size: clamp(2.5rem, 12vw, 4.5rem);
  font-weight: 900;
  letter-spacing: 0.08em;
}

.message.is-error {
  color: var(--danger);
  font-weight: 700;
}

@media (max-width: 560px) {
  .app {
    width: min(100% - 18px, 760px);
    padding: 14px 0;
  }

  .card {
    gap: 18px;
    padding: 20px;
  }

  .input-row {
    grid-template-columns: 1fr;
  }
}