:root {
  --bg: #f6f7f9;
  --panel: #fff;
  --line: #e2e5ea;
  --text: #1f2733;
  --muted: #6b7480;
  --accent: #2f6f4f;
  --error: #c0392b;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", "Hiragino Kaku Gothic ProN", "Meiryo", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}
.topbar {
  display: flex; align-items: center; justify-content: space-between;
  padding: 10px 16px; background: var(--panel); border-bottom: 1px solid var(--line);
}
.brand { font-weight: 700; color: var(--text); text-decoration: none; }
.topnav { display: flex; align-items: center; gap: 12px; }
.who { color: var(--muted); font-size: 14px; }
.logout-form { margin: 0; }
.link-btn { background: none; border: none; color: var(--accent); cursor: pointer; font-size: 14px; }
.content { max-width: 960px; margin: 0 auto; padding: 20px 16px; }
.muted { color: var(--muted); }
.error { color: var(--error); }
.notice { color: var(--accent); background: #eaf5ef; padding: 8px 10px; border-radius: 6px; }

/* login */
.login-wrap { max-width: 360px; margin: 8vh auto; background: var(--panel); padding: 28px; border: 1px solid var(--line); border-radius: 10px; }
.login-form { display: flex; flex-direction: column; gap: 14px; }
.login-form label { display: flex; flex-direction: column; gap: 4px; font-size: 14px; color: var(--muted); }
.login-form input { padding: 10px; font-size: 16px; border: 1px solid var(--line); border-radius: 6px; }
button.primary { background: var(--accent); color: #fff; border: none; padding: 11px; font-size: 16px; border-radius: 6px; cursor: pointer; }

.tabs-placeholder { margin-top: 16px; padding: 16px; background: var(--panel); border: 1px dashed var(--line); border-radius: 8px; }

@media (max-width: 600px) {
  .content { padding: 14px 12px; }
}