:root {
  --bg: #f4f5f7;
  --card: #ffffff;
  --ink: #1f2937;
  --muted: #6b7280;
  --line: #e5e7eb;
  --accent: #0f766e;
  --accent-hover: #0d5f58;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "PingFang SC", "Microsoft YaHei", "Noto Sans CJK SC", sans-serif;
  background: radial-gradient(circle at 10% 10%, #edf7f6 0%, var(--bg) 55%);
  color: var(--ink);
}

.container {
  width: min(980px, 92vw);
  margin: 24px auto 40px;
}

.hero h1 {
  margin: 0 0 10px;
  font-size: clamp(28px, 3.4vw, 42px);
}

.hero p {
  margin: 0 0 20px;
  color: var(--muted);
}

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 20px;
  box-shadow: 0 10px 24px rgba(15, 23, 42, 0.05);
}

fieldset {
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 12px 14px;
  margin: 14px 0;
}

legend {
  padding: 0 8px;
  color: var(--muted);
}

label {
  display: block;
  margin: 8px 0;
  line-height: 1.5;
}

.field {
  margin-bottom: 10px;
}

.field.inline {
  display: flex;
  gap: 10px;
  align-items: center;
  flex-wrap: wrap;
}

input[type="file"],
input[type="number"] {
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 8px 10px;
  background: #fff;
}

.submit-btn {
  border: none;
  border-radius: 10px;
  background: var(--accent);
  color: #fff;
  padding: 12px 18px;
  font-size: 15px;
  cursor: pointer;
  transition: background 0.2s ease;
}

.submit-btn:hover:not(:disabled) {
  background: var(--accent-hover);
}

.submit-btn:disabled {
  opacity: 0.7;
  cursor: wait;
}

.tips {
  margin-top: 18px;
  color: var(--muted);
}

.tips h2 {
  color: var(--ink);
  font-size: 18px;
}

.tips code {
  background: #f3f4f6;
  border: 1px solid #e5e7eb;
  border-radius: 6px;
  padding: 2px 6px;
}