/*
 * layout.css — 侧边栏 / 主区域 / 导航 / 响应式
 */

/* ── Sidebar ── */
#sidebar {
  width: 250px;
  min-height: 100vh;
  background: var(--bg2);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  position: fixed;
  left: 0; top: 0;
  z-index: 100;
  transition: transform .3s;
}

#sb-head { padding: 22px 18px; border-bottom: 1px solid var(--border); }
#sb-head .logo { font-size: 11px; color: var(--green); letter-spacing: 3px; text-transform: uppercase; margin-bottom: 7px; }
#sb-head h1 { font-size: 14px; color: var(--text); font-weight: normal; line-height: 1.6; }

#prog-wrap { padding: 14px 18px; border-bottom: 1px solid var(--border); }
#prog-wrap .lbl { font-size: 11px; color: var(--dim); margin-bottom: 7px; display: flex; justify-content: space-between; }
#prog-bar { height: 3px; background: var(--border); border-radius: 2px; }
#prog-fill { height: 100%; background: linear-gradient(90deg, var(--green), var(--cyan)); border-radius: 2px; transition: width .5s; width: 0; }

#ch-nav { flex: 1; overflow-y: auto; padding: 10px 0; }

/* ── Nav items ── */
.nv {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 9px 18px;
  cursor: pointer;
  transition: all .2s;
  border-left: 2px solid transparent;
  font-size: 13px;
  color: var(--dim);
}
.nv:hover  { background: rgba(255,255,255,.03); color: var(--text); }
.nv.active {
  border-left-color: var(--green);
  color: var(--green);
  background: rgba(0,255,136,.07);
  box-shadow: inset 0 0 18px rgba(0,255,136,.06);
}
.nv.done   { color: var(--cyan); }

.nd { width: 7px; height: 7px; border-radius: 50%; border: 1px solid currentColor; flex-shrink: 0; }
.nv.done   .nd { background: var(--cyan); }
.nv.active .nd { background: var(--green); box-shadow: 0 0 8px var(--green); }

/* ── Main area ── */
#main { margin-left: 250px; flex: 1; min-height: 100vh; }

.sec { display: none; min-height: 100vh; padding: 40px; max-width: 880px; }
.sec.active {
  display: block;
  animation: sec-in .35s ease both;
}

@keyframes sec-in {
  from { opacity: 0; transform: translateY(14px); }
  to   { opacity: 1; transform: translateY(0); }
}

@media (prefers-reduced-motion: reduce) {
  .sec.active { animation: none; }
}

/* ── Mobile menu button ── */
#menu-btn {
  display: none;
  position: fixed;
  top: 14px; right: 14px;
  z-index: 200;
  background: var(--bg2);
  border: 1px solid var(--border);
  padding: 7px 11px;
  cursor: pointer;
  color: var(--green);
  font-family: inherit;
  font-size: 13px;
}

/* ── Responsive ── */
@media (max-width: 768px) {
  #sidebar { transform: translateX(-100%); width: 230px; }
  #sidebar.open { transform: translateX(0); }
  #main { margin-left: 0; }
  #menu-btn { display: block; }
  .sec { padding: 20px; padding-top: 56px; }
}