.sidebar{
  width: min(var(--sidebarW), 88vw);
  position: fixed;
  inset: 0 auto 0 0;
  height: 100vh;
  height: 100dvh;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
  z-index: 1000;

  background: rgba(255,255,255,.88);
  backdrop-filter: blur(14px);
  border-right: 1px solid var(--border);
  box-shadow: 0 10px 30px rgba(0,0,0,.06);

  transform: translateX(0);
  transition: transform .28s ease;
  will-change: transform;

  /* Keep navigation readable even when a course page changes global text tokens. */
  color: #111827;
}

.sidebar .menu-title,
.sidebar .submenu button:not(.active),
.sidebar .submenu a,
.sidebar .subject-link{
  color: #111827;
  -webkit-text-fill-color: #111827;
  opacity: 1;
}

#sidebar-area .sidebar{
  background: #f8fafc;
}

.sidebar.open{
  transform: translateX(0);
}

.sidebar-toggle-btn{
  position: absolute;
  top: 12px;
  right: 12px;
  border: 0;
  padding: 6px 10px;
  border-radius: 999px;
  background: rgba(229,57,53,.12);
  color: var(--brand2);
  font-weight: 800;
  cursor: pointer;
  display: none;
}

.sidebar-head{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:12px;
  padding: 12px 14px;
  border-bottom: 1px solid rgba(0,0,0,.06);
  background: linear-gradient(180deg, rgba(255,255,255,.96), rgba(245,247,252,.92));
}

.logo{
  padding: 8px 12px;
  font-weight: 900;
  letter-spacing: .2px;
  font-size: 18px;
  color: #111;
  display:flex;
  align-items:center;
  gap:10px;
  text-decoration: none;
  background: #fff;
  border: 1px solid rgba(0,0,0,.08);
  border-radius: 14px;
  box-shadow: 0 10px 24px rgba(0,0,0,.08);
}
.logo::before{ content: none; }

.home-icon{
  width: 26px;
  height: 26px;
  display:inline-flex;
  align-items:center;
  justify-content:center;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--brand), var(--brand2));
  box-shadow: 0 8px 18px rgba(229,57,53,.22);
}
.home-icon svg{
  width: 16px;
  height: 16px;
  fill: #fff;
}

.sidebar-hide-btn{
  border: 1px solid rgba(0,0,0,.08);
  cursor: pointer;
  padding: 8px 12px;
  border-radius: 12px;
  font-weight: 900;
  background: linear-gradient(135deg, rgba(255,255,255,.96), rgba(245,245,245,.92));
  color: #111;
  box-shadow: 0 10px 22px rgba(0,0,0,.10);
  transition: transform .18s ease, box-shadow .18s ease;
}
.sidebar-hide-btn:hover{
  transform: translateY(-1px);
  box-shadow: 0 10px 22px rgba(0,0,0,.10);
}

.sidebar-user{
  margin: 10px 12px 12px;
  padding: 12px;
  border-radius: 14px;
  border: 1px solid rgba(0,0,0,.08);
  background: linear-gradient(180deg, rgba(255,255,255,.96), rgba(247,250,255,.92));
  box-shadow: 0 10px 20px rgba(0,0,0,.08);
}

.sidebar-user-label{
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: .7px;
  color: #64748b;
  font-weight: 800;
}

.sidebar-user-name{
  margin-top: 4px;
  font-weight: 900;
  font-size: 16px;
  color: #0f172a;
  word-break: break-word;
}

.sidebar-user-email{
  margin-top: 2px;
  font-size: 12px;
  color: #475569;
  word-break: break-all;
}

.sidebar-install-btn{
  margin-top: 10px;
  border: 0;
  padding: 9px 12px;
  border-radius: 10px;
  background: linear-gradient(135deg, #059669, #10b981);
  color: #fff;
  font-weight: 800;
  cursor: pointer;
  box-shadow: 0 10px 20px rgba(16,185,129,.22);
}

.sidebar-install-btn:disabled{
  cursor: default;
  opacity: .72;
  box-shadow: none;
}

.sidebar-install-note{
  margin-top: 8px;
  font-size: 12px;
  line-height: 1.45;
  color: #475569;
}

body.install-guide-open{
  overflow: hidden;
}

.install-guide-modal{
  position: fixed;
  inset: 0;
  z-index: 3000;
  display: grid;
  place-items: center;
  padding: 18px;
}

.install-guide-modal[hidden]{
  display: none;
}

.install-guide-backdrop{
  position: absolute;
  inset: 0;
  background: rgba(2,6,23,.62);
  backdrop-filter: blur(5px);
}

.install-guide-panel{
  position: relative;
  width: min(560px, calc(100vw - 28px));
  border-radius: 24px;
  padding: 22px;
  background: linear-gradient(165deg, rgba(255,255,255,.98), rgba(240,253,244,.96));
  border: 1px solid rgba(255,255,255,.85);
  box-shadow: 0 30px 70px rgba(2,6,23,.28);
}

.install-guide-close{
  position: absolute;
  top: 12px;
  right: 12px;
  width: 38px;
  height: 38px;
  border: 0;
  border-radius: 999px;
  background: rgba(15,23,42,.08);
  color: #0f172a;
  font-size: 28px;
  line-height: 1;
  cursor: pointer;
}

.install-guide-kicker{
  margin: 0;
  font-size: 12px;
  font-weight: 800;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: #059669;
}

.install-guide-title{
  margin: 10px 0 8px;
  font-size: 30px;
  line-height: 1.08;
  color: #052e16;
}

.install-guide-intro{
  margin: 0;
  color: #334155;
  line-height: 1.65;
}

.install-guide-shortcut{
  margin-top: 14px;
  display: inline-flex;
  align-items: center;
  padding: 10px 14px;
  border-radius: 14px;
  background: linear-gradient(135deg, rgba(5,150,105,.12), rgba(16,185,129,.08));
  color: #065f46;
  font-size: 15px;
  font-weight: 900;
  letter-spacing: .01em;
}

.install-guide-steps{
  margin: 14px 0 0;
  padding-left: 20px;
  display: grid;
  gap: 8px;
  color: #0f172a;
  line-height: 1.5;
  font-weight: 700;
}

.install-guide-actions{
  margin-top: 18px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.install-guide-primary,
.install-guide-secondary{
  border: 0;
  border-radius: 12px;
  padding: 11px 16px;
  font-weight: 800;
  cursor: pointer;
}

.install-guide-primary{
  background: linear-gradient(135deg, #059669, #10b981);
  color: #fff;
  box-shadow: 0 12px 24px rgba(16,185,129,.22);
}

.install-guide-secondary{
  background: rgba(15,23,42,.08);
  color: #0f172a;
}


@media (max-width: 768px){
  .sidebar{
    transform: translateX(-110%);
    z-index: 2200;
  }
  .sidebar.open{
    transform: translateX(0);
  }
  .sidebar-toggle-btn{
    display: inline-flex;
    align-items: center;
    justify-content: center;
  }

  .sidebar-hide-btn{
    display: none;
  }
}

@media (max-width: 768px){
  .mobile-menu-btn{
    display: inline-flex;
    align-items: center;
    justify-content: center;
    top: max(12px, env(safe-area-inset-top));
    left: max(12px, env(safe-area-inset-left));
    z-index: 2300;
    min-width: 48px;
    min-height: 44px;
    touch-action: manipulation;
  }

  body.sidebar-open{
    overflow: hidden;
  }

  body.sidebar-open .mobile-menu-btn{
    display: none;
  }
}

body.sidebar-collapsed .sidebar{
  transform: translateX(-110%);
}
body.sidebar-collapsed .mobile-menu-btn{
  display: block;
}
body.sidebar-collapsed.has-fixed-teacher .teacher-banner.teacher-banner-fixed{
  left: 16px;
  right: 16px;
}