:root {
  --bg: #f7f8fa;
  --card: #ffffff;
  --primary: #2f6df6;
  --primary-dark: #1f55d4;
  --text: #1f2937;
  --muted: #6b7280;
  --border: #e5e7eb;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 24px;
  background: var(--card);
  border-bottom: 1px solid var(--border);
}

.brand { font-weight: 700; font-size: 18px; }

nav #navUser { color: var(--muted); font-size: 14px; }

main {
  max-width: 480px;
  margin: 48px auto;
  padding: 0 16px;
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 28px;
  box-shadow: 0 4px 18px rgba(0,0,0,.04);
}

.tabs { display: flex; gap: 8px; margin-bottom: 18px; }

.tab {
  flex: 1;
  padding: 10px;
  border: 1px solid var(--border);
  background: #fff;
  border-radius: 10px;
  cursor: pointer;
  font-size: 15px;
  color: var(--muted);
}
.tab.active { border-color: var(--primary); color: var(--primary); font-weight: 600; }

form { display: flex; flex-direction: column; gap: 12px; }

input {
  padding: 12px 14px;
  border: 1px solid var(--border);
  border-radius: 10px;
  font-size: 15px;
  outline: none;
}
input:focus { border-color: var(--primary); }

.btn {
  padding: 12px 16px;
  border: none;
  border-radius: 10px;
  font-size: 15px;
  cursor: pointer;
}
.btn.primary { background: var(--primary); color: #fff; }
.btn.primary:hover { background: var(--primary-dark); }
.btn.ghost { background: transparent; border: 1px solid var(--border); color: var(--muted); margin-top: 18px; }

.msg { font-size: 13px; min-height: 18px; margin: 0; }
.msg.err { color: #dc2626; }
.msg.ok { color: #16a34a; }

.home-card h1 { margin: 0 0 6px; font-size: 22px; }
.home-card .sub { color: var(--muted); margin: 0 0 20px; }
.placeholder {
  background: #f1f5ff;
  border: 1px dashed #c7d6ff;
  border-radius: 12px;
  padding: 28px;
  text-align: center;
  color: var(--muted);
}
.placeholder .hint { font-size: 13px; }

.foot { text-align: center; color: var(--muted); font-size: 13px; padding: 24px; }