:root {
  --platform-sidebar-w: 224px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

body.has-platform-sidebar {
  margin: 0;
  padding-left: var(--platform-sidebar-w);
}

.platform-sidebar {
  position: fixed;
  left: 0;
  top: 0;
  width: var(--platform-sidebar-w);
  height: 100vh;
  height: 100dvh;
  background: var(--sidebar, #0d121a);
  border-right: 1px solid var(--line-soft, #1b2634);
  display: flex;
  flex-direction: column;
  z-index: 120;
  overflow: auto;
}

.platform-sidebar-brand {
  padding: 24px 22px 16px;
  border-bottom: 1px solid var(--line-soft, #1b2634);
  flex-shrink: 0;
}

.platform-sidebar-brand .brand-row {
  display: flex;
  align-items: center;
  gap: 11px;
  color: inherit;
  text-decoration: none;
}

.platform-sidebar-brand .brand-row:hover .logo {
  color: #fff;
}

.platform-sidebar-brand .platform-logo-mark {
  width: 34px;
  height: 34px;
  flex: 0 0 auto;
  display: block;
  filter: drop-shadow(0 8px 18px rgba(83, 111, 215, 0.28));
}

.platform-sidebar-brand .logo {
  margin-bottom: 2px;
  color: var(--text, #e8edf4);
  font-size: 0.92rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.platform-sidebar-brand h2 {
  margin: 0;
  color: var(--muted, #8b98a8);
  font-size: 0.68rem;
  font-weight: 450;
  line-height: 1.35;
}

.platform-sidebar-nav {
  flex: 1 1 auto;
  min-height: 0;
  padding: 12px 14px 16px;
  display: flex;
  flex-direction: column;
  gap: 5px;
}

.platform-nav-group {
  flex-shrink: 0;
}

.platform-nav-group summary {
  cursor: pointer;
  list-style: none;
}

.platform-nav-chevron {
  width: 15px;
  height: 15px;
  margin-left: auto;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.7;
  transition: transform 0.16s;
}

.platform-nav-group[open] .platform-nav-chevron {
  transform: rotate(180deg);
}

.platform-nav-sublist {
  display: grid;
  gap: 3px;
  margin: 4px 0 7px 29px;
  padding-left: 10px;
  border-left: 1px solid var(--line, #253142);
}

.platform-nav-subitem {
  min-height: 32px;
  padding: 7px 10px;
  border-radius: 8px;
  color: #8795a8;
  text-decoration: none;
  font-size: 0.76rem;
}

.platform-nav-subitem:hover,
.platform-nav-subitem.current {
  background: var(--accent-dim, rgba(119, 149, 255, 0.12));
  color: #eaf0ff;
}

.platform-nav-item {
  display: flex;
  align-items: center;
  gap: 10px;
  min-height: 42px;
  padding: 0 12px;
  border-radius: 10px;
  color: #a7b2c2;
  text-decoration: none;
  font-size: 0.86rem;
  border: 1px solid transparent;
  flex-shrink: 0;
  margin: 0;
  transition: background 0.15s, border-color 0.15s;
}

.platform-nav-item:hover {
  background: var(--surface-2, #151e29);
  border-color: var(--line-soft, #1b2634);
}

.platform-nav-item.current {
  background: var(--accent-dim, rgba(119, 149, 255, 0.12));
  border-color: rgba(119, 149, 255, 0.25);
  color: #eaf0ff;
}

.platform-nav-item .icon {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
  stroke: currentColor;
  fill: none;
  stroke-width: 1.75;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.platform-nav-item.current .icon {
  stroke: var(--accent-bright, #9aacff);
}

.lang-switch {
  display: inline-flex;
  border: 1px solid var(--line, #253142);
  border-radius: 8px;
  overflow: hidden;
  background: var(--surface-2, #151e29);
}

.lang-btn {
  margin: 0;
  border: 0;
  background: transparent;
  color: var(--muted, #8d9aae);
  font: inherit;
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  padding: 6px 10px;
  cursor: pointer;
}

.lang-btn + .lang-btn {
  border-left: 1px solid var(--line, #253142);
}

.lang-btn:hover {
  color: var(--text, #f3f6fb);
}

.lang-btn.active {
  color: var(--text, #f3f6fb);
  background: var(--accent-dim, rgba(119, 149, 255, 0.12));
}