:root {
  --fg: #1f2328;
  --muted: #6b7280;
  --bg: #f6f7f9;
  --panel: #ffffff;
  --border: #d9dde3;
  --accent: #2563eb;
  --accent-fg: #ffffff;
  --danger: #b91c1c;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font: 15px/1.5 system-ui, -apple-system, "Segoe UI", sans-serif;
  color: var(--fg);
  background: var(--bg);
}

a { color: var(--accent); }
h1 { font-size: 1.5rem; margin: 0 0 1rem; }
.muted { color: var(--muted); }

/* Top nav */
.topnav {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  padding: 0 1.25rem;
  height: 3rem;
  background: var(--panel);
  border-bottom: 1px solid var(--border);
}
.topnav .brand { font-weight: 600; }
.topnav nav { display: flex; gap: 1rem; flex: 1; }
.topnav nav a { color: var(--fg); text-decoration: none; }
.topnav nav a.active { font-weight: 600; }
.topnav nav .disabled { color: var(--muted); opacity: 0.6; cursor: default; }
.logout { margin: 0; }

/* Shell: sidebar + main */
.shell { display: flex; min-height: calc(100vh - 3rem); }
.sidebar {
  width: 15rem;
  flex-shrink: 0;
  padding: 1rem;
  background: var(--panel);
  border-right: 1px solid var(--border);
}
.sidebar h2 {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--muted);
  margin: 1rem 0 0.25rem;
}
.sidebar section:first-child h2 { margin-top: 0; }
.sidebar h2 a { color: inherit; text-decoration: none; }
.sidebar h2 a:hover { text-decoration: underline; }
.sidebar ul { list-style: none; margin: 0; padding: 0; }
.sidebar li a {
  display: block;
  padding: 0.25rem 0.5rem;
  border-radius: 4px;
  color: var(--fg);
  text-decoration: none;
}
.sidebar li a:hover { background: var(--bg); }
.sidebar li a[aria-current="page"] { background: var(--accent); color: var(--accent-fg); }
.sidebar li.muted { padding: 0.25rem 0.5rem; }
main { flex: 1; padding: 1.5rem; min-width: 0; }

/* Cards */
.card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 1.5rem;
}
.card.narrow { max-width: 24rem; margin: 3rem auto; }

/* Forms */
label { display: block; font-weight: 500; margin-bottom: 0.25rem; }
input[type="text"], input[type="email"], input[type="search"], textarea, select {
  display: block;
  width: 100%;
  padding: 0.5rem;
  margin-bottom: 1rem;
  font: inherit;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: var(--panel);
}
textarea { min-height: 12rem; }
.error { color: var(--danger); }

/* Buttons */
button, .button {
  display: inline-block;
  padding: 0.45rem 0.9rem;
  font: inherit;
  color: var(--accent-fg);
  background: var(--accent);
  border: 1px solid var(--accent);
  border-radius: 4px;
  cursor: pointer;
  text-decoration: none;
}
button.secondary { color: var(--fg); background: var(--panel); border-color: var(--border); }
button.danger { background: var(--danger); border-color: var(--danger); }
button.button-link { padding: 0; color: var(--accent); background: none; border: none; }
button:disabled { opacity: 0.5; cursor: not-allowed; }

/* Tables */
table { width: 100%; border-collapse: collapse; background: var(--panel); }
th, td { text-align: left; padding: 0.5rem 0.75rem; border-bottom: 1px solid var(--border); }
th { font-weight: 600; color: var(--muted); font-size: 0.85rem; }

/* Stacked cards and code */
main .card + .card { margin-top: 1rem; }
dl { display: grid; grid-template-columns: max-content 1fr; gap: 0.5rem 1.5rem; }
dt { color: var(--muted); }
dd { margin: 0; white-space: pre-line; }
pre { overflow-x: auto; padding: 0.75rem; background: var(--bg); border: 1px solid var(--border); border-radius: 4px; }

/* List tabs, subscriber tools and pager */
.tabs { display: flex; gap: 1rem; margin-bottom: 1rem; border-bottom: 1px solid var(--border); }
.tabs a { padding: 0.5rem 0; color: var(--muted); text-decoration: none; }
.tabs a[aria-current="page"] { color: var(--fg); border-bottom: 2px solid var(--accent); }
.tools { display: flex; flex-wrap: wrap; gap: 1rem; margin-bottom: 1rem; }
.tools form { display: flex; gap: 0.5rem; }
.pager { display: flex; gap: 1rem; margin-top: 0.75rem; }
.notice { color: var(--accent); }

/* Campaign editor: form beside its live preview. */
.editor { display: grid; grid-template-columns: repeat(auto-fit, minmax(22rem, 1fr)); gap: 1rem; align-items: start; }
main .editor .card + .card { margin-top: 0; }
.actions { display: flex; flex-wrap: wrap; gap: 0.5rem; margin-top: 1rem; }
iframe.preview { width: 100%; min-height: 36rem; border: 1px solid var(--border); border-radius: 4px; background: #fff; }