diff --git a/src/hqt/tui/screens/new_session.py b/src/hqt/tui/screens/new_session.py
index 2b43fd6..2b24413 100644
--- a/src/hqt/tui/screens/new_session.py
+++ b/src/hqt/tui/screens/new_session.py
@@ -1,4 +1,5 @@
 from textual.app import ComposeResult
+from textual.binding import Binding
 from textual.containers import Horizontal, Vertical
 from textual.screen import ModalScreen
 from textual.widgets import Button, Checkbox, Input, Label, Select, Switch
@@ -10,6 +11,14 @@ from hqt.sandbox import SandboxPolicy
 class NewSessionScreen(
     ModalScreen[tuple[str, str, str | None, str | None, SandboxPolicy | None] | None]
 ):
+    # Soft vim-style field navigation: j/k walk the dialog's focus chain. Inputs
+    # consume printable keys first, so j/k type literally while editing text and
+    # only move focus when a toggle/select/button is focused.
+    BINDINGS = [
+        Binding("j", "focus_next", "Next field", show=False),
+        Binding("k", "focus_previous", "Prev field", show=False),
+    ]
+
     def __init__(
         self,
         harness_names: list[str],
@@ -21,6 +30,14 @@ class NewSessionScreen(
         self.sandbox_available = sandbox_available
         super().__init__()
 
+    # focus_next/focus_previous are screen methods, not binding actions, so the
+    # j/k bindings need these thin action_* wrappers to dispatch to them.
+    def action_focus_next(self) -> None:
+        self.focus_next()
+
+    def action_focus_previous(self) -> None:
+        self.focus_previous()
+
     def compose(self) -> ComposeResult:
         with Vertical(id="new-session-dialog"):
             yield Label("New Session")
@@ -63,15 +80,20 @@ class NewSessionScreen(
                     "bubblewrap not found — run `hqt doctor`",
                     id="sandbox-warning",
                 )
-            yield Label("Filesystem access:")
-            yield Select(
-                [("Read-write", "rw"), ("Read-only", "ro")],
-                id="fs-select",
-                value="rw",
-                allow_blank=False,
-            )
-            yield Label("Network:")
-            yield Switch(id="net-switch", value=True)
+            # Sub-options of the sandbox switch: only meaningful when sandboxing
+            # is on, so hidden until then (mirrors the worktree -> branch reveal).
+            sandbox_options = Vertical(id="sandbox-options")
+            sandbox_options.display = False
+            with sandbox_options:
+                yield Label("Filesystem access:")
+                yield Select(
+                    [("Read-write", "rw"), ("Read-only", "ro")],
+                    id="fs-select",
+                    value="rw",
+                    allow_blank=False,
+                )
+                yield Label("Network:")
+                yield Switch(id="net-switch", value=True)
             with Horizontal(classes="dialog-actions"):
                 yield Button("OK", variant="primary", id="ok-btn")
                 yield Button("Cancel", id="cancel-btn")
@@ -89,6 +111,11 @@ class NewSessionScreen(
         else:
             branch_input.display = False
 
+    def on_switch_changed(self, event: Switch.Changed) -> None:
+        if event.switch.id != "sandbox-switch":
+            return
+        self.query_one("#sandbox-options", Vertical).display = event.value
+
     def on_button_pressed(self, event: Button.Pressed) -> None:
         if event.button.id == "ok-btn":
             self._submit()
diff --git a/src/hqt/tui/styles.tcss b/src/hqt/tui/styles.tcss
index 359a427..b71a6cd 100644
--- a/src/hqt/tui/styles.tcss
+++ b/src/hqt/tui/styles.tcss
@@ -90,3 +90,15 @@ ProjectFormScreen, NewSessionScreen, SchedulePromptScreen {
     background: $surface-lighten-1;
     color: $foreground;
 }
+
+/* Unify the focus highlight across the New Session dialog. The buttons get a
+   Peach $accent focus highlight (above), but Switch/Checkbox/Select/Input
+   otherwise fall back to Textual's default Lavender $border focus border, which
+   reads as off-palette next to the buttons. Match `tall` so only the color
+   changes, not the control height. */
+#new-session-dialog Switch:focus,
+#new-session-dialog Checkbox:focus,
+#new-session-dialog Select:focus,
+#new-session-dialog Input:focus {
+    border: tall $accent;
+}
diff --git a/tests/test_tui.py b/tests/test_tui.py
index 77b2111..dd99b55 100644
--- a/tests/test_tui.py
+++ b/tests/test_tui.py
@@ -1869,3 +1869,117 @@ async def test_poll_sessions_dispatches_due_prompts_and_notifies():
 
         mock_service.dispatch_due_prompts.assert_awaited_once()
         assert any("Prompt sent" in call[0] for call in notify_calls)
+
+
+@pytest.mark.asyncio
+async def test_sandbox_options_hidden_until_switch_on():
+    """The fs/net rows are sub-options of the sandbox switch: hidden until it is
+    turned on, shown when on, hidden again when turned back off."""
+    app = HqtApp()
+    async with app.run_test(size=(120, 40)) as pilot:
+        from hqt.tui.screens.new_session import NewSessionScreen
+        from textual.widgets import Switch
+
+        app.push_screen(
+            NewSessionScreen(["claude"], is_git_repo=True, sandbox_available=True)
+        )
+        await pilot.pause()
+        options = app.screen.query_one("#sandbox-options")
+        assert options.display is False
+
+        switch = app.screen.query_one("#sandbox-switch", Switch)
+        switch.value = True
+        await pilot.pause()
+        assert options.display is True
+
+        switch.value = False
+        await pilot.pause()
+        assert options.display is False
+
+
+def test_dialog_focus_highlight_uses_accent():
+    """Every focusable control in the New Session dialog shares the Peach accent
+    focus border (consistent with the dialog buttons), not Textual's default
+    Lavender. Guards against the scoped :focus rule being dropped."""
+    from pathlib import Path
+    import hqt.tui
+
+    css = (Path(hqt.tui.__file__).parent / "styles.tcss").read_text()
+    for selector in (
+        "#new-session-dialog Switch:focus",
+        "#new-session-dialog Checkbox:focus",
+        "#new-session-dialog Select:focus",
+        "#new-session-dialog Input:focus",
+    ):
+        assert selector in css, f"missing focus rule: {selector}"
+    assert "border: tall $accent;" in css
+
+
+def test_new_session_has_jk_focus_bindings():
+    """j -> focus_next, k -> focus_previous, declared on the screen."""
+    from hqt.tui.screens.new_session import NewSessionScreen
+
+    actions = {b.key: b.action for b in NewSessionScreen.BINDINGS}
+    assert actions.get("j") == "focus_next"
+    assert actions.get("k") == "focus_previous"
+
+
+@pytest.mark.asyncio
+async def test_jk_moves_focus_between_controls():
+    """On a non-text control, j moves focus to another control."""
+    app = HqtApp()
+    async with app.run_test(size=(120, 40)) as pilot:
+        from hqt.tui.screens.new_session import NewSessionScreen
+        from textual.widgets import Switch
+
+        app.push_screen(
+            NewSessionScreen(["claude"], is_git_repo=True, sandbox_available=True)
+        )
+        await pilot.pause()
+        switch = app.screen.query_one("#sandbox-switch", Switch)
+        switch.focus()
+        await pilot.pause()
+        assert app.focused is switch
+
+        await pilot.press("j")
+        await pilot.pause()
+        assert app.focused is not switch
+
+
+@pytest.mark.asyncio
+async def test_jk_typed_into_input_is_literal():
+    """Inside a text input, j/k type literally and do not move focus."""
+    app = HqtApp()
+    async with app.run_test(size=(120, 40)) as pilot:
+        from hqt.tui.screens.new_session import NewSessionScreen
+        from textual.widgets import Input
+
+        app.push_screen(NewSessionScreen(["claude"], is_git_repo=True))
+        await pilot.pause()
+        nickname = app.screen.query_one("#nickname-input", Input)
+        nickname.focus()
+        await pilot.pause()
+
+        await pilot.press("j", "k")
+        await pilot.pause()
+        assert nickname.value == "jk"
+        assert app.focused is nickname
+
+
+def test_policy_is_none_when_sandbox_off_regardless_of_suboptions():
+    """When sandboxing is off, the (now hidden) fs/net sub-option values are
+    discarded — the submitted policy is None no matter what they hold."""
+    from hqt.tui.screens.new_session import NewSessionScreen
+
+    assert NewSessionScreen._policy_from(False, "ro", False) is None
+    assert NewSessionScreen._policy_from(False, "rw", True) is None
+
+
+def test_policy_reflects_suboptions_when_sandbox_on():
+    """When sandboxing is on, the fs/net sub-option values flow into the policy."""
+    from hqt.tui.screens.new_session import NewSessionScreen
+
+    policy = NewSessionScreen._policy_from(True, "ro", False)
+    assert policy is not None
+    assert policy.fs == "ro"
+    assert policy.net is False