:root {
  --bg: #081325;
  --bg-soft: #0d1c34;
  --sidebar-top: #112a52;
  --sidebar-bottom: #07162b;
  --border: rgba(255, 255, 255, 0.08);
  --text: #eaf1fb;
  --menu-bg: rgba(52, 98, 168, 0.45);
  --menu-border: rgba(75, 128, 214, 0.55);
  --menu-active: rgba(32, 128, 96, 0.55);
  --content-bg: #ffffff;
  --radius: 16px;
  --sidebar-width: 380px;
  --font: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  font-family: var(--font);
  background: var(--bg);
}

body {
  min-height: 100vh;
}

.app {
  display: grid;
  grid-template-columns: var(--sidebar-width) 1fr;
  min-height: 100vh;
}

.sidebar {
  background: linear-gradient(180deg, var(--sidebar-top), var(--sidebar-bottom));
  border-right: 1px solid var(--border);
  padding: 18px 14px;
  overflow-y: auto;
}

.brand {
  padding: 10px 6px 18px;
  margin-bottom: 12px;
  border-bottom: 1px solid rgba(255,255,255,0.08);
}

.brand h1 {
  margin: 0;
  color: var(--text);
  font-size: 2.2rem;
  font-weight: 700;
  letter-spacing: 0.01em;
}

.menu-section {
  margin-bottom: 18px;
}

.menu-section h2 {
  margin: 0 0 10px;
  font-size: 0.78rem;
  font-weight: 700;
  text-transform: uppercase;
  color: #d6e3f7;
}

.menu-item {
  width: 100%;
  text-align: left;
  border: 1px solid var(--menu-border);
  background: var(--menu-bg);
  color: #ffffff;
  border-radius: 16px;
  padding: 12px 14px;
  margin-bottom: 10px;
  cursor: pointer;
  font: inherit;
}

.menu-item .title {
  display: block;
  font-size: 1rem;
  font-weight: 500;
}

.menu-item.active {
  background: var(--menu-active);
}

.menu-section-bottom {
  padding-top: 6px;
}

.content {
  min-width: 0;
  background: #ffffff;
}

.viewer {
  padding: 0;
  height: 100vh;
  background: #ffffff;
}

iframe {
  display: block;
  width: 100%;
  height: 100vh;
  border: 0;
  background: #ffffff;
}

@media (max-width: 980px) {
  .app {
    grid-template-columns: 1fr;
  }

  .sidebar {
    width: 100%;
    border-right: 0;
    border-bottom: 1px solid var(--border);
  }

  .viewer,
  iframe {
    height: calc(100vh - 420px);
    min-height: 500px;
  }
}