*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg: #1a1a1a;
  --bg2: #242424;
  --bg3: #2e2e2e;
  --border: #3a3a3a;
  --text: #e0e0e0;
  --text-dim: #888;
  --accent: #4a9eff;
  --danger: #e05555;
  --sidebar-w: 260px;
  --tab-h: 36px;
  --toolbar-h: 36px;
}

html, body { height: 100%; font: 14px/1.4 'Menlo', 'Consolas', monospace; background: var(--bg); color: var(--text); }

.hidden { display: none !important; }
.error { color: var(--danger); font-size: 12px; min-height: 18px; }

/* --- Login --- */
#login-screen {
  display: flex; align-items: center; justify-content: center; height: 100vh;
}
.login-box {
  background: var(--bg2); border: 1px solid var(--border); border-radius: 8px;
  padding: 40px 36px; width: 320px;
}
.login-box h1 { font-size: 18px; margin-bottom: 24px; color: var(--accent); }
.login-box input {
  display: block; width: 100%; padding: 8px 10px; margin-bottom: 12px;
  background: var(--bg3); border: 1px solid var(--border); border-radius: 4px;
  color: var(--text); font: inherit;
}
.login-box input:focus { outline: none; border-color: var(--accent); }
.login-box button {
  width: 100%; padding: 9px; background: var(--accent); border: none;
  border-radius: 4px; color: #fff; font: inherit; cursor: pointer; margin-bottom: 10px;
}
.login-box button:hover { filter: brightness(1.1); }

/* --- App layout --- */
#app { display: flex; height: 100vh; overflow: hidden; }

/* --- Sidebar --- */
#sidebar {
  width: var(--sidebar-w); min-width: var(--sidebar-w);
  background: var(--bg2); border-right: 1px solid var(--border);
  display: flex; flex-direction: column; overflow: hidden;
}
#sidebar-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 8px 10px; border-bottom: 1px solid var(--border); flex-shrink: 0;
}
#sidebar-cwd { font-size: 11px; color: var(--text-dim); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
#sidebar-actions { display: flex; gap: 4px; flex-shrink: 0; }
.icon-btn {
  background: var(--bg3); border: 1px solid var(--border); border-radius: 3px;
  color: var(--text); cursor: pointer; font: 11px/1 monospace; padding: 3px 6px;
}
.icon-btn:hover { border-color: var(--accent); color: var(--accent); }

#file-tree { flex: 1; overflow-y: auto; padding: 4px 0; }

.tree-item {
  display: flex; align-items: center; gap: 6px;
  padding: 3px 12px; cursor: pointer; white-space: nowrap;
  user-select: none; font-size: 13px;
}
.tree-item:hover { background: var(--bg3); }
.tree-item.active { background: var(--bg3); color: var(--accent); }
.tree-item .icon { font-size: 12px; flex-shrink: 0; }
.tree-item .name { overflow: hidden; text-overflow: ellipsis; }
.tree-children { padding-left: 16px; }

/* --- Editor area --- */
#editor-area { flex: 1; display: flex; flex-direction: column; overflow: hidden; }

#editor-tabs {
  display: flex; align-items: center; height: var(--tab-h);
  border-bottom: 1px solid var(--border); background: var(--bg2);
  overflow-x: auto; flex-shrink: 0;
}
.tab {
  display: flex; align-items: center; gap: 8px;
  padding: 0 14px; height: 100%; white-space: nowrap;
  border-right: 1px solid var(--border); cursor: pointer;
  font-size: 12px; color: var(--text-dim);
}
.tab:hover { background: var(--bg3); }
.tab.active { background: var(--bg); color: var(--text); }
.tab.dirty::before { content: '●'; color: var(--accent); margin-right: 4px; }
.tab-close {
  font-size: 14px; color: var(--text-dim); line-height: 1;
  padding: 0 2px; border-radius: 2px;
}
.tab-close:hover { background: var(--bg3); color: var(--text); }

#editor-toolbar {
  display: flex; align-items: center; justify-content: space-between;
  height: var(--toolbar-h); padding: 0 12px;
  border-bottom: 1px solid var(--border); background: var(--bg); flex-shrink: 0;
}
#editor-filename { font-size: 12px; color: var(--text-dim); }
#editor-actions { display: flex; gap: 8px; }
#editor-actions button {
  padding: 3px 12px; font: 12px/1 monospace; cursor: pointer;
  border-radius: 3px; border: 1px solid var(--border);
}
#btn-save { background: var(--accent); color: #fff; border-color: var(--accent); }
#btn-save:hover { filter: brightness(1.1); }
#btn-download { background: var(--bg3); color: var(--text); }
#btn-download:hover { border-color: var(--accent); }

#editor-container { flex: 1; overflow: hidden; }
#editor-container .CodeMirror { height: 100%; font-size: 13px; }

#editor-empty {
  flex: 1; display: flex; align-items: center; justify-content: center;
  color: var(--text-dim);
}

/* --- Context menu --- */
#ctx-menu {
  position: fixed; z-index: 100; background: var(--bg2);
  border: 1px solid var(--border); border-radius: 4px;
  list-style: none; padding: 4px 0; min-width: 140px;
  box-shadow: 0 4px 12px rgba(0,0,0,.5);
}
#ctx-menu li {
  padding: 6px 16px; cursor: pointer; font-size: 13px;
}
#ctx-menu li:hover { background: var(--bg3); }
#ctx-menu li.danger { color: var(--danger); }

/* Scrollbar */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }