opencode/packages/ui/src/components/message-nav.css

[data-component="message-nav"] {
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  padding-left: 0;
  list-style: none;

  &[data-size="normal"] {
    width: 240px;
    gap: 4px;
  }
}

[data-slot="message-nav-item"] {
  display: flex;
  align-items: center;
  align-self: stretch;
  justify-content: flex-end;

  [data-component="message-nav"][data-size="normal"] & {
    justify-content: flex-start;
  }
}

[data-slot="message-nav-tick-button"] {
  display: flex;
  align-items: center;
  justify-content: flex-start;
  height: 12px;
  width: 24px;
  border: none;
  background: none;
  padding: 0;

  &[data-active] [data-slot="message-nav-tick-line"] {
    background-color: var(--icon-strong-base);
    width: 100%;
  }
}

[data-slot="message-nav-tick-line"] {
  height: 1px;
  width: 16px;
  background-color: var(--icon-base);
  transition:
    width 0.2s,
    background-color 0.2s;
}

[data-slot="message-nav-tick-button"]:hover [data-slot="message-nav-tick-line"] {
  width: 100%;
  background-color: var(--icon-strong-base);
}

[data-slot="message-nav-message-button"] {
  display: flex;
  align-items: center;
  align-self: stretch;
  width: 100%;
  column-gap: 12px;
  cursor: default;
  border: none;
  background: none;
  padding: 4px 12px;
  border-radius: var(--radius-sm);
}

[data-slot="message-nav-title-preview"] {
  font-size: 14px; /* text-14-regular */
  color: var(--text-weak);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  min-width: 0;
  text-align: left;

  &[data-active] {
    color: var(--text-strong);
  }
}

[data-slot="message-nav-item"]:hover [data-slot="message-nav-message-button"] {
  background-color: var(--surface-base);
}
[data-slot="message-nav-item"]:active [data-slot="message-nav-message-button"] {
  background-color: var(--surface-base-active);
}

[data-slot="message-nav-item"]:active [data-slot="message-nav-title-preview"] {
  color: var(--text-base);
}

[data-slot="message-nav-tooltip"] {
  z-index: 1000;
}

[data-slot="message-nav-tooltip-content"] {
  display: flex;
  padding: 4px 4px 6px 4px;
  justify-content: center;
  align-items: center;
  border-radius: var(--radius-md);
  background: var(--surface-raised-stronger-non-alpha);

  /* border/shadow-xs/base */
  box-shadow:
    0 0 0 1px var(--border-weak-base, rgba(17, 0, 0, 0.12)),
    0 1px 2px -1px rgba(19, 16, 16, 0.04),
    0 1px 2px 0 rgba(19, 16, 16, 0.06),
    0 1px 3px 0 rgba(19, 16, 16, 0.08);

  * {
    margin: 0 !important;
  }
}