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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background-color: #1a1a1a;
  color: #e0e0e0;
}

/* ── App shell ──────────────────────────────────── */
.app {
  height: 100vh;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  overscroll-behavior: none;
}

/* ── Header ─────────────────────────────────────── */
.app-header {
  background-color: #252526;
  border-bottom: 1px solid #007acc;
  padding: 0 16px;
  height: 44px;
  flex-shrink: 0;
  display: flex;
  align-items: center;
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
}

.header-brand {
  display: flex;
  align-items: center;
  gap: 10px;
}

.header-title {
  font-size: 15px;
  font-weight: 600;
  color: #e0e0e0;
  letter-spacing: 0.2px;
}

.examples-link {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  background: transparent;
  color: #9d9d9d;
  text-decoration: none;
  border-radius: 5px;
  font-size: 13px;
  font-weight: 500;
  border: 1px solid #3a3a3a;
  transition: all 0.15s;
}

.examples-link:hover {
  background: #2a2d2e;
  color: #fff;
  border-color: #555;
}

/* ── Main panels container ──────────────────────── */
.app-container {
  flex: 1;
  display: flex;
  overflow: hidden;
  position: relative;
}

.editor-panel {
  display: flex;
  flex-direction: row;
  flex-shrink: 0;
  overflow: hidden;
  min-width: 20%;
  max-width: 80%;
}

/* Toggle button for the file explorer sidebar */
.explorer-toggle-btn {
  width: 36px;
  flex-shrink: 0;
  background: #252526;
  border: none;
  border-right: 1px solid #333;
  border-bottom: 1px solid #333;
  color: #7a7a7a;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.1s, color 0.1s;
}

.explorer-toggle-btn:hover {
  background: #2a2d2e;
  color: #ccc;
}

/* Resize handle for the file explorer sidebar */
.explorer-resize-handle {
  width: 4px;
  flex-shrink: 0;
  cursor: col-resize;
  background: #2a2a2a;
  transition: background 0.15s;
  position: relative;
  z-index: 5;
}

.explorer-resize-handle:hover,
.explorer-resize-handle:active {
  background: #007acc;
}

.editor-wrapper {
  flex: 1;
  overflow: hidden;
}

.simulator-panel {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  min-width: 20%;
}

/* ── Resize handle ──────────────────────────────── */
.resize-handle {
  width: 5px;
  flex-shrink: 0;
  background: #2a2a2a;
  cursor: col-resize;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.15s;
  position: relative;
  z-index: 10;
}

.resize-handle:hover,
.resize-handle:active {
  background: #007acc;
}

.resize-handle-grip {
  width: 2px;
  height: 32px;
  background: #444;
  border-radius: 2px;
  transition: background 0.15s;
}

.resize-handle:hover .resize-handle-grip,
.resize-handle:active .resize-handle-grip {
  background: rgba(255, 255, 255, 0.5);
}

/* ── Responsive ─────────────────────────────────── */
@media (max-width: 768px) {
  .app-container {
    flex-direction: column;
  }

  .editor-panel,
  .simulator-panel {
    width: 100% !important;
    min-width: unset;
    max-width: unset;
    flex: 1;
  }

  .resize-handle {
    display: none;
  }
}

/* ── Mobile tab bar ──────────────────────────────── */
.mobile-tab-bar {
  display: none;
}

@media (max-width: 768px) {
  .mobile-tab-bar {
    display: flex;
    flex-shrink: 0;
    height: 54px;
    background: #252526;
    border-top: 1px solid #007acc;
    z-index: 50;
  }

  .mobile-tab-btn {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 3px;
    background: transparent;
    border: none;
    color: #7a7a7a;
    font-size: 11px;
    font-weight: 500;
    cursor: pointer;
    transition: color 0.15s, background 0.15s;
    padding: 6px 0;
  }

  .mobile-tab-btn--active {
    color: #007acc;
    background: rgba(0, 122, 204, 0.08);
  }

  .mobile-tab-btn:active {
    background: rgba(255, 255, 255, 0.06);
  }
}

/* ── Header responsive ───────────────────────────── */
@media (max-width: 768px) {
  .app-header {
    padding: 0 10px;
    height: 44px;
  }

  .examples-link span,
  .header-github-text,
  .header-username-text {
    display: none;
  }

  .examples-link {
    padding: 6px 8px;
  }
}