:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --danger: #dc2626;
  --success: #16a34a;
  --warning: #d97706;
  --bg: #f5f7fb;
  --card: #ffffff;
  --text: #1f2937;
  --text-2: #6b7280;
  --border: #e5e7eb;
  --radius: 12px;
}

* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  font-size: 15px;
  line-height: 1.5;
}

/* 顶部导航（后台） */
.navbar {
  background: #1f2937;
  color: #fff;
  padding: 12px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: sticky;
  top: 0;
  z-index: 50;
}
.navbar .brand { font-weight: 600; font-size: 16px; }
.navbar a, .navbar button {
  color: #fff;
  background: transparent;
  border: none;
  cursor: pointer;
  font-size: 14px;
  text-decoration: none;
  margin-left: 12px;
}

.card {
  background: var(--card);
  border-radius: var(--radius);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
  padding: 20px;
  margin-bottom: 16px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 10px 18px;
  border-radius: 10px;
  border: none;
  cursor: pointer;
  font-size: 15px;
  font-weight: 500;
  background: var(--primary);
  color: #fff;
  text-decoration: none;
  transition: opacity 0.15s;
}
.btn:hover { opacity: 0.9; }
.btn:disabled { opacity: 0.45; cursor: not-allowed; }
.btn-block { width: 100%; }
.btn-outline { background: #fff; color: var(--primary); border: 1px solid var(--primary); }
.btn-danger { background: var(--danger); }
.btn-ghost { background: #eef2ff; color: var(--primary); }
.btn-sm { min-height: 34px; padding: 6px 12px; font-size: 13px; border-radius: 8px; }

.input, select.input, textarea.input {
  width: 100%;
  min-height: 44px;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 10px;
  font-size: 15px;
  background: #fff;
  color: var(--text);
}
.input:focus { outline: none; border-color: var(--primary); box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.12); }
label { display: block; font-size: 13px; color: var(--text-2); margin: 12px 0 6px; }

table { width: 100%; border-collapse: collapse; }
th, td { text-align: left; padding: 10px 12px; border-bottom: 1px solid var(--border); font-size: 14px; }
th { color: var(--text-2); font-weight: 600; background: #f9fafb; }

.muted { color: var(--text-2); }
.small { font-size: 13px; }
.tag { display: inline-block; padding: 2px 8px; border-radius: 999px; font-size: 12px; background: #eef2ff; color: var(--primary); }
.tag-green { background: #ecfdf5; color: var(--success); }
.tag-red { background: #fef2f2; color: var(--danger); }
.tag-gray { background: #f3f4f6; color: var(--text-2); }

.toast {
  display: none;
  position: fixed;
  top: 16px;
  left: 50%;
  transform: translateX(-50%);
  background: #111827;
  color: #fff;
  padding: 10px 18px;
  border-radius: 10px;
  z-index: 999;
  font-size: 14px;
  max-width: 80vw;
}
.toast-error { background: var(--danger); }

.spinner {
  width: 18px; height: 18px;
  border: 2px solid rgba(255,255,255,0.4);
  border-top-color: #fff;
  border-radius: 50%;
  display: inline-block;
  animation: spin 0.7s linear infinite;
  vertical-align: -3px;
  margin-right: 6px;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* 模态框 */
.modal-mask {
  position: fixed; inset: 0; background: rgba(0,0,0,0.45);
  display: none; align-items: center; justify-content: center; z-index: 200; padding: 20px;
}
.modal-mask.show { display: flex; }
.modal {
  background: #fff; border-radius: 14px; padding: 22px;
  width: 100%; max-width: 460px; max-height: 85vh; overflow: auto;
}
.modal h3 { margin: 0 0 12px; }