A helm display in sunlight, a tablet after dusk, and a screen beside a sleeping berth should not all emit the same light. BoatKit gives every Viewer its own Day, Night, and Overnight appearances, so one display can adapt without changing screens elsewhere aboard.
Normal switching follows the device appearance, calculated sunset and sunrise, or a fixed Day or Night choice. Overnight is a separate override with a much darker, red-led palette designed to reduce contrast and emitted light during night navigation or in a sleeping cabin. Compatible native Viewers enable their device light or brightness signal by default, while each Viewer can turn that behavior off or use a schedule instead.
The appearance is applied across the whole operating surface—not only page backgrounds. Selected controls, chart labels and track history, water-depth bands, map points, and wind, slip, pitch, roll, tide, and current indicators all use theme-owned roles so bright daytime accents do not leak into the overnight display.
Schedule or sense the change
An overnight schedule can cross midnight and follows the local clock on that Viewer. Native mobile apps can instead use the signal their platform makes available: supported Android devices report ambient illumination in lux, while iPhone and iPad report display brightness as an explicit proxy. The current reading appears beside adjustable entry and exit thresholds.
BoatKit waits for darkness to persist before entering Overnight and uses a separate, higher exit threshold before returning to the normal Day or Night palette. That hysteresis prevents a passing light, shadow, or briefly covered sensor from making the display flash between appearances.
Every device reports its real capability. Android hardware without a light sensor and viewers without a supported native signal hide the device-signal option and stay schedule-capable rather than inventing an environmental reading.
Choose a comfortable interface size
Compact, high-resolution screens can make controls feel too small. Interface scale in This Viewer Preferences enlarges the interface relative to the browser’s normal sizing while preserving display resolution. Ordinary Viewers apply the change immediately and remember it locally. On a BoatKit device’s attached display, the same picker also sizes the on-screen keyboard and clearly explains the browser restart needed to apply a change.
The managed Raspberry Pi HDMI display can also be mounted in portrait orientation. Its attached-display setting rotates the picture and matching touchscreen input together, and saves that choice on the BoatKit device for the next boot.