:root {
  --bg: #f4f7fb;
  --panel: #fff;
  --text: #152238;
  --muted: #6b7c99;
  --line: #e3eaf5;
  --brand: #0369a1;
}

* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background: var(--bg);
}
a { color: var(--brand); text-decoration: none; }
button, input, textarea, select { font: inherit; }

.admin-login-page {
  min-height: 100vh;
  display: grid;
  place-items: center;
  background: linear-gradient(160deg, #0b1630, #0c4a6e);
}
.login-card {
  width: min(400px, calc(100% - 2rem));
  background: #fff;
  border-radius: 16px;
  padding: 1.6rem;
  display: grid;
  gap: 0.8rem;
}
.login-card h1 { margin: 0; font-size: 1.35rem; }
.login-card p { margin: 0; color: var(--muted); }
.login-card label { display: grid; gap: 0.35rem; }
.login-card input {
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 0.75rem 0.9rem;
}
.login-card button {
  border: 0;
  border-radius: 10px;
  background: var(--brand);
  color: #fff;
  padding: 0.8rem;
  cursor: pointer;
}
.login-card .error { color: #c0392b; }

.admin-body {
  display: grid;
  grid-template-columns: 220px 1fr;
  min-height: 100vh;
}
.admin-side {
  background: #101b33;
  color: #dbe7ff;
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}
.side-brand { font-weight: 700; letter-spacing: 0.04em; }
.admin-side nav { display: grid; gap: 0.35rem; }
.admin-side a {
  color: #b7c7e8;
  padding: 0.55rem 0.7rem;
  border-radius: 8px;
}
.admin-side a.active,
.admin-side a:hover { background: rgba(255, 255, 255, 0.08); color: #fff; }
.admin-side form { margin-top: auto; }
.admin-side button {
  width: 100%;
  border: 1px solid rgba(255, 255, 255, 0.2);
  background: transparent;
  color: #fff;
  border-radius: 8px;
  padding: 0.6rem;
  cursor: pointer;
}

.admin-main { padding: 1.5rem; }
.admin-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1rem;
  flex-wrap: wrap;
}
.admin-top h1 { margin: 0; font-size: 1.4rem; }
.top-actions { display: flex; gap: 0.5rem; flex-wrap: wrap; }
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.55rem 0.9rem;
  border-radius: 8px;
  background: var(--brand);
  color: #fff;
  border: 0;
  cursor: pointer;
}
.btn.ghost { background: #fff; color: var(--text); border: 1px solid var(--line); }
.btn.danger { background: #c0392b; }

.stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 0.9rem;
  margin-bottom: 1.2rem;
}
.stat-card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 1rem;
}
.stat-card .n { font-size: 1.6rem; font-weight: 700; }
.stat-card .l { color: var(--muted); font-size: 0.85rem; margin-top: 0.25rem; }

.table-wrap {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 12px;
  overflow: auto;
}
table { width: 100%; border-collapse: collapse; }
th, td {
  padding: 0.85rem 0.9rem;
  border-bottom: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}
th { background: #f8fafc; font-size: 0.9rem; color: var(--muted); }
.muted { color: var(--muted); font-size: 0.85rem; }
.actions { display: flex; gap: 0.6rem; align-items: center; flex-wrap: wrap; }
.actions form { margin: 0; }
.actions button.link-danger {
  border: 0; background: transparent; color: #c0392b; cursor: pointer; padding: 0;
}

.edit-form {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 1.2rem;
  display: grid;
  gap: 0.9rem;
  max-width: 860px;
}
.edit-form label { display: grid; gap: 0.35rem; }
.edit-form input,
.edit-form textarea,
.edit-form select {
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 0.7rem 0.8rem;
}
.edit-form .row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.9rem;
}
.form-alert {
  margin: 0 0 0.4rem;
  padding: 0.7rem 0.85rem;
  border-radius: 8px;
  font-size: 0.92rem;
}
.form-alert.ok { background: #e8f8ef; color: #0d7a45; }
.form-alert.err { background: #fdeceb; color: #c0392b; }
.cover-preview {
  width: 120px; height: 120px; object-fit: cover;
  border-radius: 8px; border: 1px solid var(--line); margin-bottom: 0.4rem;
}
.cover-preview.wide { width: 100%; max-width: 420px; height: 140px; }
.form-section-title {
  margin: 0.6rem 0 0; font-size: 1.05rem;
  padding-top: 0.4rem; border-top: 1px solid var(--line);
}
.form-section-title:first-of-type { border-top: 0; padding-top: 0; }
.field-hint { color: var(--muted); font-size: 0.82rem; }
.icon-preview { display: inline-flex; align-items: center; gap: 0.4rem; color: var(--brand); }

@media (max-width: 800px) {
  .admin-body { grid-template-columns: 1fr; }
  .admin-side { flex-direction: row; flex-wrap: wrap; align-items: center; }
  .admin-side nav { display: flex; flex-wrap: wrap; }
  .admin-side form { margin-top: 0; margin-left: auto; }
  .edit-form .row { grid-template-columns: 1fr; }
}