:root {
  --bg-primary: #0a0a0a;
  --bg-secondary: #0d1117;
  --surface: #161b22;
  --surface-light: #1c2333;
  --border: #30363d;
  --text-primary: #e6edf3;
  --text-secondary: #8b949e;
  --accent: #a855f7;
  --accent-dim: rgba(168,85,247,0.15);
  --green: #4ade80;
  --blue: #58a6ff;
  --amber: #f59e0b;
  --red: #f87171;
  --taskbar-height: 36px;
  --font-mono: 'Cascadia Code','Fira Code','JetBrains Mono','Menlo','Monaco','Consolas','Courier New',monospace;
  --font-size: 13px;
  --font-size-sm: 11px;
  --radius: 8px;
}

:root[data-accent="green"] { --accent: #4ade80; --accent-dim: rgba(74,222,128,0.15); }
:root[data-accent="blue"] { --accent: #58a6ff; --accent-dim: rgba(88,166,255,0.15); }
:root[data-accent="amber"] { --accent: #f59e0b; --accent-dim: rgba(245,158,11,0.15); }

*,*::before,*::after { margin:0; padding:0; box-sizing:border-box; }
html,body { height:100%; overflow:hidden; }
body {
  background:var(--bg-primary); color:var(--text-primary);
  font-family:var(--font-mono); font-size:var(--font-size);
  line-height:1.5; -webkit-font-smoothing:antialiased;
  user-select:none;
}
::selection { background:var(--accent-dim); }
::-webkit-scrollbar { width:5px; }
::-webkit-scrollbar-track { background:transparent; }
::-webkit-scrollbar-thumb { background:var(--border); border-radius:3px; }
::-webkit-scrollbar-thumb:hover { background:var(--text-secondary); }

/* ===== BACKGROUND ===== */
#particle-canvas { position:fixed; top:0; left:0; width:100%; height:100%; z-index:0; pointer-events:none; }
#grid-overlay {
  position:fixed; top:0; left:0; width:100%; height:100%; z-index:1; pointer-events:none;
  background-image:linear-gradient(rgba(88,166,255,0.025) 1px,transparent 1px),linear-gradient(90deg,rgba(88,166,255,0.025) 1px,transparent 1px);
  background-size:60px 60px;
}

/* ===== DESKTOP ===== */
#desktop { position:fixed; top:0; left:0; right:0; bottom:var(--taskbar-height); z-index:2; }
#desktop-icons { position:absolute; top:16px; left:16px; display:flex; flex-direction:column; gap:8px; }


.desktop-icon {
  display:flex; flex-direction:column; align-items:center; width:76px; padding:10px 6px 8px;
  cursor:pointer; border-radius:var(--radius); transition:background 0.15s; text-align:center;
  background:transparent; border:none; color:var(--text-primary); font-family:inherit; font-size:var(--font-size-sm);
}
.desktop-icon:hover { background:rgba(255,255,255,0.08); }
.desktop-icon:active { background:rgba(255,255,255,0.12); }
.desktop-icon-icon {
  width:44px; height:44px; display:flex; align-items:center; justify-content:center;
  font-size:22px; margin-bottom:4px;
}
.desktop-icon-label { word-break:break-word; line-height:1.3; }

/* ===== WINDOWS ===== */
#windows-container { position:fixed; top:0; left:0; right:0; bottom:var(--taskbar-height); z-index:10; pointer-events:none; }
.window {
  position:absolute; border-radius:var(--radius); border:1px solid var(--border);
  box-shadow:0 8px 32px rgba(0,0,0,0.6); background:var(--surface);
  display:flex; flex-direction:column; pointer-events:auto;
  min-width:280px; min-height:160px;
  transition:opacity 0.2s, transform 0.2s, border-radius 0.2s, box-shadow 0.2s;
}
.window.focused { border-color:var(--accent); box-shadow:0 8px 32px rgba(0,0,0,0.6), 0 0 0 1px var(--accent-dim); }
.window.minimized { opacity:0; transform:scale(0.9); pointer-events:none; }
.window.maximized {
  border-radius:0; border-left:none; border-right:none; border-top:none;
  top:0 !important; left:0 !important; width:100% !important; height:100% !important;
  box-shadow:none;
}

.window-titlebar {
  display:flex; align-items:center; padding:6px 10px; background:var(--bg-secondary);
  border-bottom:1px solid var(--border); flex-shrink:0; cursor:default;
  border-radius:var(--radius) var(--radius) 0 0;
}
.window.maximized .window-titlebar { border-radius:0; }

.window-controls { display:flex; gap:6px; margin-right:10px; }
.win-btn {
  width:12px; height:12px; border-radius:50%; border:none; cursor:pointer;
  transition:filter 0.15s, transform 0.15s; display:block; padding:0;
}
.win-btn:hover { filter:brightness(1.3); transform:scale(1.15); }
.win-btn.close { background:#ff5f56; }
.win-btn.minimize { background:#ffbd2e; }
.win-btn.maximize { background:#27c93f; }

.window-title-text {
  flex:1; text-align:center; font-size:var(--font-size-sm); color:var(--text-secondary);
  margin-right:40px; white-space:nowrap; overflow:hidden; text-overflow:ellipsis;
}

.window-content {
  flex:1; overflow:auto; padding:0; display:flex; flex-direction:column;
  min-height:0;
}

/* ===== TASKBAR ===== */
#taskbar {
  position:fixed; bottom:0; left:0; right:0; height:var(--taskbar-height);
  background:rgba(13,17,23,0.96); border-top:1px solid var(--border);
  z-index:100; display:flex; align-items:center; padding:0 6px;
  backdrop-filter:blur(8px); -webkit-backdrop-filter:blur(8px);
}
#taskbar-left, #taskbar-right { display:flex; align-items:center; gap:4px; flex-shrink:0; }
#taskbar-center { flex:1; display:flex; align-items:center; gap:4px; justify-content:center; overflow-x:auto; padding:0 8px; }

#launcher-btn {
  background:transparent; border:1px solid var(--border); border-radius:4px;
  color:var(--accent); font-family:inherit; font-size:12px; font-weight:700;
  padding:2px 10px; cursor:pointer; height:26px; transition:all 0.15s;
}
#launcher-btn:hover { background:var(--accent-dim); border-color:var(--accent); }

.taskbar-item {
  background:transparent; border:none; color:var(--text-secondary); font-family:inherit;
  font-size:11px; padding:2px 10px; cursor:pointer; border-radius:4px;
  height:26px; transition:all 0.15s; white-space:nowrap;
}
.taskbar-item:hover { background:var(--surface-light); color:var(--text-primary); }
.taskbar-item.active { background:var(--accent-dim); color:var(--accent); border-bottom:2px solid var(--accent); border-radius:4px 4px 0 0; }
.taskbar-item.minimized { opacity:0.5; }

#taskbar-clock { color:var(--text-secondary); font-size:11px; padding:0 8px; font-variant-numeric:tabular-nums; }

#launcher-menu {
  position:fixed; bottom:calc(var(--taskbar-height) + 4px); left:6px;
  z-index:200; background:var(--surface); border:1px solid var(--border);
  border-radius:var(--radius); padding:6px; min-width:200px;
  box-shadow:0 8px 32px rgba(0,0,0,0.5); transition:opacity 0.15s, transform 0.15s;
}
#launcher-menu.hidden { opacity:0; transform:scale(0.95); pointer-events:none; }

.launcher-item {
  display:flex; align-items:center; gap:10px; width:100%; padding:8px 12px;
  background:transparent; border:none; color:var(--text-primary); font-family:inherit;
  font-size:13px; cursor:pointer; border-radius:4px; transition:background 0.1s;
}
.launcher-item:hover { background:var(--accent-dim); }
.launcher-icon { font-size:18px; width:28px; text-align:center; }

/* ===== TERMINAL APP ===== */
.term-wrapper { display:flex; flex-direction:column; flex:1; min-height:0; padding:8px 10px; }
.term-output { flex:1; overflow-y:auto; min-height:0; line-height:1.5; font-size:13px; }
.term-output > div { margin-bottom:1px; }
.term-completion { flex-shrink:0; font-size:12px; min-height:0; }
.term-completion:not(:empty) { padding-top:4px; }
.term-prompt {
  flex-shrink:0; display:flex; align-items:center; padding-top:6px; font-size:13px;
  border-top:1px solid var(--border); margin-top:4px;
}
.term-input {
  flex:1; outline:none; border:none; background:transparent; color:var(--text-primary);
  font-family:inherit; font-size:inherit; caret-color:var(--accent);
  white-space:pre; word-break:break-all; min-height:1.2em;
}

/* ===== FILE MANAGER ===== */
.fm-wrapper { display:flex; flex:1; min-height:0; }
.fm-sidebar {
  width:180px; background:var(--bg-secondary); border-right:1px solid var(--border);
  overflow-y:auto; padding:6px 0; flex-shrink:0;
}
.fm-sidebar-item {
  display:flex; align-items:center; gap:6px; padding:4px 12px; cursor:pointer;
  font-size:12px; color:var(--text-secondary); transition:all 0.1s;
}
.fm-sidebar-item:hover { background:var(--surface-light); color:var(--text-primary); }
.fm-sidebar-item.active { background:var(--accent-dim); color:var(--accent); }
.fm-sidebar-item.depth-1 { padding-left:28px; }
.fm-sidebar-item.depth-2 { padding-left:44px; }
.fm-main { flex:1; display:flex; flex-direction:column; min-height:0; }
.fm-list { flex:1; overflow-y:auto; padding:4px 0; }
.fm-file {
  display:flex; align-items:center; gap:8px; padding:4px 12px; cursor:pointer;
  font-size:12px; color:var(--text-primary); transition:background 0.1s;
}
.fm-file:hover { background:var(--surface-light); }
.fm-file .fm-icon { font-size:14px; width:20px; text-align:center; }
.fm-file .fm-name { flex:1; }
.fm-file .fm-size { color:var(--text-secondary); font-size:11px; }
.fm-viewer {
  flex:1; overflow-y:auto; padding:12px; font-size:12px; white-space:pre-wrap;
  color:var(--text-primary); line-height:1.6;
}
.fm-viewer .fm-viewer-header { color:var(--text-secondary); font-size:11px; margin-bottom:8px; padding-bottom:6px; border-bottom:1px solid var(--border); }

/* ===== SYSTEM INFO ===== */
.sysinfo-wrapper { padding:20px; display:flex; gap:24px; align-items:flex-start; flex:1; }
.sysinfo-ascii {
  font-size:10px; line-height:1.2; color:var(--accent); white-space:pre;
  flex-shrink:0; letter-spacing:0;
}
.sysinfo-details { flex:1; display:flex; flex-direction:column; gap:2px; }
.sysinfo-row { display:flex; font-size:12px; padding:2px 0; }
.sysinfo-label { color:var(--text-secondary); width:80px; flex-shrink:0; }
.sysinfo-value { color:var(--text-primary); }
.sysinfo-sep { color:var(--border); padding:0 8px; }

/* ===== PHYSICS LAB ===== */
/* ===== SETTINGS ===== */
.settings-wrapper { padding:16px 20px; flex:1; overflow-y:auto; }
.settings-title { font-size:14px; font-weight:600; margin-bottom:16px; color:var(--text-primary); }
.settings-group { margin-bottom:16px; }
.settings-label { font-size:11px; color:var(--text-secondary); margin-bottom:6px; text-transform:uppercase; letter-spacing:0.5px; }
.settings-row { display:flex; gap:8px; flex-wrap:wrap; }
.settings-swatch {
  width:28px; height:28px; border-radius:50%; border:2px solid transparent; cursor:pointer;
  transition:all 0.15s;
}
.settings-swatch:hover { transform:scale(1.15); }
.settings-swatch.active { border-color:var(--text-primary); transform:scale(1.1); }
.settings-swatch.green { background:#4ade80; }
.settings-swatch.blue { background:#58a6ff; }
.settings-swatch.purple { background:#a855f7; }
.settings-swatch.amber { background:#f59e0b; }
.settings-toggle {
  display:flex; align-items:center; gap:8px; padding:6px 0; cursor:pointer;
  font-size:12px; color:var(--text-primary);
}
.settings-toggle input[type="checkbox"] { accent-color:var(--accent); }
.settings-btn {
  background:var(--accent-dim); border:1px solid var(--accent); color:var(--accent);
  font-family:inherit; font-size:12px; padding:4px 16px; border-radius:4px;
  cursor:pointer; transition:all 0.15s;
}
.settings-btn:hover { background:var(--accent); color:#000; }
.settings-about { font-size:12px; color:var(--text-secondary); line-height:1.8; margin-top:8px; }

/* ===== PHYSICS KNOWLEDGE ===== */
.pkw-wrapper { display:flex; flex:1; min-height:0; }
.pkw-sidebar {
  width:200px; background:var(--bg-secondary); border-right:1px solid var(--border);
  overflow-y:auto; padding:6px 0; flex-shrink:0;
}
.pkw-cat {
  display:flex; align-items:center; gap:8px; width:100%; padding:7px 14px;
  background:transparent; border:none; color:var(--text-secondary); font-family:inherit;
  font-size:12px; cursor:pointer; text-align:left; transition:all 0.12s;
}
.pkw-cat:hover { background:var(--surface-light); color:var(--text-primary); }
.pkw-cat.active { background:var(--accent-dim); color:var(--accent); border-left:2px solid var(--accent); }
.pkw-cat-icon { font-size:15px; width:22px; text-align:center; flex-shrink:0; }
.pkw-cat-name { white-space:nowrap; overflow:hidden; text-overflow:ellipsis; }

.pkw-main { flex:1; display:flex; flex-direction:column; min-height:0; }
.pkw-header { padding:10px 16px; font-size:14px; font-weight:600; color:var(--accent); border-bottom:1px solid var(--border); flex-shrink:0; }
.pkw-grid {
  flex:1; overflow-y:auto; padding:12px; display:grid;
  grid-template-columns:repeat(auto-fill,minmax(260px,1fr)); gap:10px; align-content:start;
}
.pkw-placeholder { grid-column:1/-1; color:var(--text-secondary); font-size:13px; padding:40px; text-align:center; }

.pkw-card {
  background:var(--surface-light); border:1px solid var(--border); border-radius:6px;
  padding:12px 14px; cursor:pointer; transition:all 0.2s;
  animation:pkwFadeIn 0.4s ease-out both;
  display:flex; flex-direction:column; gap:6px;
}
.pkw-card:hover { border-color:var(--accent); transform:translateY(-2px); box-shadow:0 4px 16px rgba(0,0,0,0.3); }
.pkw-card.expanded { border-color:var(--accent); background:var(--surface); }
.pkw-card-title { font-size:13px; font-weight:600; color:var(--text-primary); }
.pkw-card-desc { font-size:11px; color:var(--text-secondary); line-height:1.5; }
.pkw-card-footer { display:flex; justify-content:space-between; align-items:center; margin-top:auto; }
.pkw-card-level { font-size:11px; font-weight:600; }
.pkw-card-count { font-size:10px; color:var(--text-secondary); }
.pkw-card-formulas {
  display:none; flex-wrap:wrap; gap:4px; padding-top:6px; margin-top:6px;
  border-top:1px solid var(--border);
}
.pkw-card.expanded .pkw-card-formulas { display:flex; }
.pkw-formula {
  font-family:'Times New Roman',serif; font-style:italic; font-size:13px;
  color:var(--accent); padding:2px 8px; background:var(--accent-dim); border-radius:3px;
}

@keyframes pkwFadeIn { from{opacity:0;transform:translateY(10px)scale(0.97)} to{opacity:1;transform:none} }

/* ===== PROJECTS ===== */
.prj-wrapper { display:flex; flex-direction:column; flex:1; min-height:0; }
.prj-toolbar {
  display:flex; align-items:center; justify-content:space-between; padding:8px 14px;
  background:var(--bg-secondary); border-bottom:1px solid var(--border); flex-shrink:0;
}
.prj-toolbar-left { display:flex; align-items:center; gap:10px; }
.prj-toolbar-title { font-size:13px; font-weight:600; color:var(--text-primary); }
.prj-count { font-size:11px; color:var(--text-secondary); }
.prj-toolbar-right { display:flex; align-items:center; gap:8px; }
.prj-sort {
  background:var(--surface); border:1px solid var(--border); border-radius:4px;
  color:var(--text-primary); font-family:inherit; font-size:11px; padding:3px 8px;
  cursor:pointer; outline:none; transition:border-color 0.15s;
}
.prj-sort:hover, .prj-sort:focus { border-color:var(--accent); }

.prj-status {
  display:flex; align-items:center; gap:8px; padding:20px; font-size:12px;
  color:var(--text-secondary); justify-content:center;
}
.prj-status-error { color:var(--red); }
.prj-spinner {
  display:inline-block; width:14px; height:14px; border:2px solid var(--border);
  border-top-color:var(--accent); border-radius:50%; animation:prjSpin 0.6s linear infinite;
}
@keyframes prjSpin { to { transform:rotate(360deg) } }

.prj-list { flex:1; overflow-y:auto; min-height:0; padding:4px 0; }
.prj-empty { padding:30px; text-align:center; color:var(--text-secondary); font-size:13px; }

.prj-row {
  display:flex; align-items:flex-start; gap:10px; padding:8px 14px; cursor:pointer;
  transition:background 0.12s; animation:prjRowIn 0.3s ease-out both;
}
.prj-row:hover { background:var(--surface-light); }
.prj-row:active { background:var(--accent-dim); }
@keyframes prjRowIn { from{opacity:0;transform:translateX(-8px)} to{opacity:1;transform:none} }

.prj-row-icon { font-size:16px; line-height:1.4; flex-shrink:0; padding-top:1px; }
.prj-row-body { flex:1; min-width:0; }
.prj-row-name { font-size:13px; font-weight:600; margin-bottom:2px; display:flex; align-items:center; gap:6px; }
.prj-row-name a { color:var(--accent); text-decoration:none; transition:color 0.15s; }
.prj-row-name a:hover { color:#79c0ff; text-decoration:underline; }
.prj-row-desc { font-size:11px; color:var(--text-secondary); line-height:1.5; margin-bottom:4px; }
.prj-row-meta { display:flex; align-items:center; gap:12px; font-size:11px; flex-wrap:wrap; }

.prj-lang-dot { display:inline-block; width:8px; height:8px; border-radius:50%; margin-right:3px; vertical-align:middle; }
.prj-lang { color:var(--text-secondary); vertical-align:middle; }
.prj-stars { color:var(--amber); }
.prj-fork { font-size:9px; color:var(--text-secondary); background:var(--surface-light); padding:1px 5px; border-radius:3px; border:1px solid var(--border); }
.prj-updated { color:var(--text-secondary); }

/* ===== BROWSER ===== */
.brw-wrapper { display:flex; flex-direction:column; flex:1; min-height:0; }
.brw-nav {
  display:flex; align-items:center; gap:4px; padding:6px 8px;
  background:var(--bg-secondary); border-bottom:1px solid var(--border); flex-shrink:0;
}
.brw-btn {
  background:transparent; border:1px solid var(--border); border-radius:3px;
  color:var(--text-secondary); font-size:12px; width:26px; height:24px;
  cursor:pointer; display:flex; align-items:center; justify-content:center;
  transition:all 0.12s; flex-shrink:0; padding:0;
}
.brw-btn:hover { background:var(--surface-light); color:var(--text-primary); border-color:var(--accent); }
.brw-btn.brw-ext { font-size:14px; width:30px; }
.brw-url-bar {
  flex:1; display:flex; align-items:center; background:var(--surface);
  border:1px solid var(--border); border-radius:4px; padding:0 8px; min-width:0;
  height:24px;
}
.brw-url-input {
  flex:1; background:transparent; border:none; outline:none; color:var(--text-primary);
  font-family:var(--font-mono); font-size:11px; min-width:0;
}
.brw-loading {
  display:none; width:12px; height:12px; border:2px solid var(--border);
  border-top-color:var(--accent); border-radius:50%; animation:brwSpin 0.5s linear infinite;
  flex-shrink:0;
}
@keyframes brwSpin { to { transform:rotate(360deg) } }

.brw-body { flex:1; position:relative; min-height:0; overflow:hidden; }
.brw-iframe-wrap { position:absolute; top:0; left:0; width:100%; height:100%; }
.brw-iframe { width:100%; height:100%; border:none; background:#fff; }

.brw-fallback {
  position:absolute; top:0; left:0; width:100%; height:100%; overflow-y:auto;
  display:flex; flex-direction:column; align-items:center; justify-content:center;
  padding:30px; background:var(--surface); text-align:center;
  animation:brwFbIn 0.3s ease-out;
}
@keyframes brwFbIn { from{opacity:0;transform:translateY(10px)} to{opacity:1;transform:none} }
.brw-fb-icon { font-size:36px; margin-bottom:12px; }
.brw-fb-title { font-size:16px; font-weight:600; color:var(--text-primary); margin-bottom:6px; }
.brw-fb-desc { font-size:12px; color:var(--text-secondary); max-width:420px; line-height:1.6; margin-bottom:12px; }
.brw-fb-meta { display:flex; flex-wrap:wrap; gap:8px; justify-content:center; margin-bottom:14px; }
.brw-fb-meta-item { font-size:11px; color:var(--text-primary); background:var(--surface-light); padding:4px 10px; border-radius:4px; border:1px solid var(--border); display:flex; align-items:center; gap:4px; }
.brw-fb-label { color:var(--text-secondary); margin-right:4px; }
.brw-lang-dot { display:inline-block; width:8px; height:8px; border-radius:50%; }
.brw-fb-note { font-size:11px; color:var(--text-secondary); max-width:400px; line-height:1.5; margin-bottom:14px; }
.brw-fb-btn {
  background:var(--accent-dim); border:1px solid var(--accent); color:var(--accent);
  font-family:inherit; font-size:13px; padding:7px 24px; border-radius:5px;
  cursor:pointer; transition:all 0.15s;
}
.brw-fb-btn:hover { background:var(--accent); color:#000; }

/* ===== ANIMATIONS ===== */
@keyframes pulse { 0%,100%{opacity:1} 50%{opacity:0.35} }
@keyframes fadeIn { from{opacity:0;transform:translateY(8px)} to{opacity:1;transform:translateY(0)} }
.window { animation:fadeIn 0.2s ease-out; }

/* ===== RESPONSIVE ===== */
@media (max-width:768px) {
  #desktop-icons { top:10px; left:10px; gap:6px; }
  .desktop-icon { width:64px; padding:6px 4px; }
  .desktop-icon-icon { width:36px; height:36px; font-size:18px; }
  .desktop-icon-label { font-size:10px; }
  .sysinfo-wrapper { flex-direction:column; padding:12px; }
  .sysinfo-ascii { font-size:8px; }
  .fm-sidebar { width:140px; }
  .window-title-text { margin-right:0; }
  .prj-row { padding:6px 10px; }
  .prj-toolbar { flex-direction:column; gap:6px; align-items:stretch; }
  .prj-toolbar-right { justify-content:flex-end; }
  .brw-nav { flex-wrap:wrap; gap:2px; }
  .brw-url-bar { min-width:100px; }
  .brw-fb-meta { flex-direction:column; align-items:center; }
}
@media (max-width:480px) {
  #launcher-menu { left:4px; right:4px; min-width:auto; }
  .fm-sidebar { width:100px; }
  .fm-sidebar-item { font-size:11px; padding:3px 8px; }
  .fm-sidebar-item.depth-1 { padding-left:20px; }
  .fm-sidebar-item.depth-2 { padding-left:32px; }
  .pkw-sidebar { width:130px; }
  .pkw-cat { font-size:11px; padding:5px 10px; }
  .pkw-grid { grid-template-columns:1fr; padding:8px; }
}