:root {
  --optm-bg: #ffffff;
  --optm-surface: #f8fafc;
  --optm-text: #0f172a;
  --optm-muted: #475569;
  --optm-border: #e2e8f0;
  --optm-accent: #0f766e;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--optm-bg);
  color: var(--optm-text);
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  line-height: 1.6;
}

.optm-shell {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 1rem;
}

.optm-site-header,
.optm-site-footer {
  border-bottom: 1px solid var(--optm-border);
  background: var(--optm-surface);
}

.optm-site-footer {
  border-top: 1px solid var(--optm-border);
  border-bottom: 0;
  margin-top: 3rem;
}

.optm-header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 72px;
  gap: 1rem;
}

.optm-brand {
  font-weight: 700;
  color: var(--optm-text);
  text-decoration: none;
}

.optm-menu-list {
  display: flex;
  align-items: center;
  gap: 1rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.optm-menu-list a {
  color: var(--optm-muted);
  text-decoration: none;
}

.optm-menu-list a:hover {
  color: var(--optm-accent);
}

.optm-site-main {
  padding-top: 2rem;
}

.optm-title {
  margin-top: 0;
  margin-bottom: 1rem;
  line-height: 1.2;
}

.optm-content img {
  max-width: 100%;
  height: auto;
}

.optm-copyright {
  margin: 1rem 0 0;
  color: var(--optm-muted);
  font-size: 0.9rem;
}