* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  color: #1c2024;
  background: radial-gradient(circle at 20% 20%, #f6f9ff 0%, #e9edf1 40%, #e1e6ec 100%);
}

.app {
  display: flex;
  min-height: 100vh;
}

.sidebar {
  width: 220px;
  background: linear-gradient(160deg, #0a0d12 0%, #121923 45%, #0b1017 100%);
  color: #e6e8ea;
  padding: 12px 10px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  box-shadow: 1px 0 0 #1b212a, 2px 0 14px rgba(12, 16, 22, 0.55);
  position: relative;
  overflow: hidden;
}

.sidebar::before {
  content: "";
  position: absolute;
  inset: -40px 20% auto auto;
  width: 140px;
  height: 140px;
  background: radial-gradient(circle, rgba(60, 180, 255, 0.35), rgba(60, 180, 255, 0));
  filter: blur(2px);
  opacity: 0.6;
  pointer-events: none;
}

.sidebar::after {
  content: "";
  position: absolute;
  inset: auto auto -60px -60px;
  width: 180px;
  height: 180px;
  background: radial-gradient(circle, rgba(120, 90, 255, 0.28), rgba(120, 90, 255, 0));
  opacity: 0.5;
  pointer-events: none;
}

.brand {
  padding: 6px 8px 8px 8px;
  border-bottom: 1px solid #1c232c;
  position: relative;
}

.brand-title {
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.6px;
  text-transform: uppercase;
  color: #eaf0f6;
}

.brand-subtitle {
  margin-top: 3px;
  font-size: 11px;
  color: #8f99a3;
  letter-spacing: 0.3px;
}

.nav {
  display: flex;
  flex-direction: column;
  gap: 4px;
  flex: 1;
}

.nav-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 7px 8px;
  border-radius: 4px;
  background: linear-gradient(135deg, rgba(15, 19, 25, 0.9), rgba(18, 25, 35, 0.95));
  color: #c9d2da;
  text-decoration: none;
  font-size: 12px;
  border: 1px solid #1b222c;
  transition: background 0.12s ease, color 0.12s ease, border-color 0.12s ease;
}

.nav-item:hover {
  background: linear-gradient(135deg, rgba(20, 30, 42, 0.95), rgba(26, 36, 50, 0.95));
  color: #ffffff;
  border-color: #233040;
}

.nav-item.active {
  background: linear-gradient(135deg, rgba(30, 48, 70, 0.95), rgba(22, 36, 52, 0.95));
  color: #ffffff;
  border-color: #2c3c52;
  box-shadow: inset 0 0 0 1px rgba(62, 120, 210, 0.5), 0 0 10px rgba(76, 160, 255, 0.2);
}

.nav-item span {
  font-size: 10px;
  color: #8b97a3;
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono",
    "Courier New", monospace;
}

.footer {
  padding: 8px 8px 4px;
  border-top: 1px solid #1c232c;
}

.footer-text a{
  text-decoration: none;
  font-size: 10px;
  color: #7f8892;
  letter-spacing: 0.4px;
  text-transform: uppercase;
}

.content {
  flex: 1;
  display: flex;
  flex-direction: column;
  padding: 0;
  gap: 6px;
  background: linear-gradient(180deg, rgba(236, 241, 246, 0.95), rgba(230, 236, 243, 0.9));
}

.content-body {
  flex: 1;
  min-height: 0;
}

.tool-frame {
  width: 100%;
  height: 100%;
  border: none;
  background: radial-gradient(circle at 20% 15%, rgba(240, 248, 255, 0.95), #f8fafc 40%, #f3f6fa 100%);
  border-radius: 2px;
  box-shadow: 0 0 0 1px #d7dce2 inset, 0 8px 20px rgba(120, 140, 170, 0.15);
}