/* Header (login.php準拠) */
.site-header{background:var(--panel); border-bottom:1px solid var(--border)}
.header-inner{
  max-width:1120px; min-height:74px; margin:0 auto; padding:14px 20px;
  display:flex; align-items:center; justify-content:space-between; gap:16px;
}
.brand{display:flex; align-items:center; gap:10px; min-width:0}
.brand-title{font-weight:800; letter-spacing:.2px; font-size:15px; white-space:nowrap}

/* ヘッダー内ボタン（login.phpの見た目に合わせてsite-header配下だけ定義） */
.site-header .btn{
  display:inline-flex; align-items:center; justify-content:center;
  padding:10px 12px;
  border-radius:10px;
  border:1px solid var(--border);
  background:var(--panel);
  color:var(--text);
  font-weight:700;
  font-size:13px;
  cursor:pointer;
  transition: background .15s ease, border-color .15s ease;
}
.site-header .btn:hover{border-color:var(--border2); background:#f9fafb}