:root{
  --bg:#f5f7fb;
  --card:#fff;
  --text:#111827;
  --muted:#6b7280;
  --accent:#6366f1;
  --border:rgba(15,23,42,.08);
  --shadow:0 18px 45px rgba(15,23,42,.08);
  --r:14px;
}

*{box-sizing:border-box}
html,body{margin:0;padding:0}
body{
  background: radial-gradient(circle at top left,#fff 0,#f5f7fb 45%,#edf0ff 100%);
  color:var(--text);
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Arial, "Noto Sans JP", sans-serif;
  line-height:1.6;
}

.page{max-width:960px;margin:0 auto;padding:20px 16px 40px}

.site-header{
  position:sticky;top:0;z-index:20;
  background:rgba(248,250,252,.9);
  backdrop-filter:blur(18px);
  border-bottom:1px solid var(--border);
}
.header-inner{max-width:960px;margin:0 auto;padding:14px 16px;display:flex;flex-direction:column;gap:4px}
.brand-title{font-size:22px;font-weight:700;letter-spacing:.03em}
.brand-subtitle{font-size:13px;color:var(--muted)}
.header-nav{margin-top:6px;font-size:13px}
.header-nav a{color:var(--accent);text-decoration:none;margin-right:12px}
.header-nav a:hover{text-decoration:underline}

.card{
  margin-top:16px;background:var(--card);border-radius:var(--r);
  padding:18px 18px 16px;box-shadow:var(--shadow);
  border:1px solid rgba(255,255,255,.7);
}

h1{margin:0 0 6px;font-size:24px;letter-spacing:.03em}
.lead{margin:0 0 10px;color:var(--muted);font-size:14px}

label{display:block;font-size:13px;margin:10px 0 4px}
input,textarea{
  width:100%;padding:10px 10px;border-radius:10px;border:1px solid var(--border);
  font-family:inherit;font-size:14px;background:#f9fafb;
}
textarea{min-height:90px;resize:vertical}

button{
  display:inline-flex;align-items:center;justify-content:center;
  padding:10px 16px;border-radius:999px;border:none;cursor:pointer;
  background:var(--accent);color:#fff;font-size:13px;
  box-shadow:0 10px 30px rgba(79,70,229,.35);
}
button.secondary{background:#e5e7eb;color:#374151;box-shadow:none}
button.danger{background:#fee2e2;color:#b91c1c;box-shadow:none}
.row{display:flex;gap:10px;flex-wrap:wrap;align-items:center;margin-top:12px}

.message{font-size:13px;margin-top:10px;white-space:pre-wrap}
.message.error{color:#dc2626}
.message.success{color:#16a34a}

.post{
  padding:14px 14px;border-radius:12px;border:1px solid var(--border);
  background:rgba(249,250,251,.9);
  margin-top:10px;
}
.post-meta{font-size:12px;color:var(--muted);margin-bottom:6px}
.post-content{font-size:14px;white-space:pre-wrap;word-break:break-word}

.badge{
  display:inline-block;padding:3px 10px;border-radius:999px;
  background:#eef0ff;color:#3730a3;font-size:12px;font-weight:600;
}