## 2 Materials and Methods
### Lighting Intervention  
In this study, a Waldmann VIAA Free Visual Timing Light lamp (VTL-lamp) and a LIFX-A60 light bulb, both shown in Figure 1, were used in the dynamic lighting system. The VTL-lamps were placed in the kitchen and in the living room near those seats where the participants spent most of the daytime. The free-floor standing luminaires provided both direct and indirect lighting via the ceiling. The illuminance level and color temperature of the light varied dynamically across the day. From 7:00 a.m. onward, the light increased quite fast across 30 min to medium level, and then more slowly from 7:30 to 9:30 a.m. until its peak value. There, it remained until 3:30 p.m., when it gradually started to decline to reach 0 lx at 9:00 p.m. The CCT started high (6000 K, quite cool, blueish light) in the morning (7:00 -9:00 a.m.) to boost the circadian rhythm. Then CCT gradually decreased to 4000 K (normal white light) and stayed there until 4:00 p.m. In the late afternoon and earlyevening, the CCT was lowered to 3000 K, and from 7:00 p.m. onward, it slowly lowered from 2500 K to 2250 K (warm yellowish light) until it was dimmed completely. The exact intensity levels depended on the exact seating position of the person, ceiling height and coloring, and shape and texture of the furniture, but were estimated as indicated in Table 2. Spectral distributions of the light varied constantly. Figure 2 visualizes the spectra in the middle of each phase described in Table 2. Full stimulus specification tables and spectra are publicly available via the Open Science Framework [41]. Measurements were taken horizontally, approximately at the lap level of a seated person, and vertically, approximately at eye level of a seated person. Both photometric illuminance and melanopic equivalent daylight (D65) illuminance (EDI\({}_{\text{mel}}\)) are reported. The first measure is most relevant to the visual system, while EDI\({}_{\text{mel}}\) is more indicative of the activation of the photoreceptors that project to the biological clock. There was a low risk of blue light hazard, the Unified Glare Rating was below 16, and there was no exposure to UV radiance. The color rendering index (Ra) was \(>\)80. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Phase**} & \multicolumn{2}{c}{**Description**} & \multirow{2}{*}{**CCT**} & \multicolumn{2}{c}{**Task Lighting**} & \multicolumn{2}{c}{**Personal Exposure**} \\  & & & & **(E\({}_{\text{horizontal}}\) at Lap Level)** & \multicolumn{2}{c}{**(E\({}_{\text{vertical}}\) at Eye Level)**} \\ \hline
**From** & **To** & **Intensity** & **Color** & & **Illuminance** & **EDI\({}_{\text{mel}}\)** & **Illuminance** & **EDI\({}_{\text{mel}}\)** \\  & & & & **(lx)** & **(lx)** & **(lx)** & **(lx)** \\ \hline
7:00 a.m. & 7:30 a.m. & Fast increase & Cool white & 6000 K & 0–1000 & 0–1100 & 0–350 & 0–370 \\
7:30 a.m. & 9:30 a.m. & Slow increase & Regular white & 6000–4000 K & 1000–2600 & 1100–2300 & 350–850 & 370–770 \\
9:30 a.m. & 3:30 p.m. & Stable & Regular white & 4000 K & 2600 & 2300 & 850 & 770 \\
3:30 p.m. & 5:30 p.m. & Slow & Warm white & 4000–3000 K & 2600–1300 & 1700–700 & 850–430 & 580–250 \\  & & dimming & & & & & \\
5:30 p.m. & 7:30 p.m. & Very slow & Warm white & 3000 K & 1300–650 & 800–300 & 430–220 & 270–100 \\
7:30 p.m. & 9:00 p.m. & Very slow & Very warm & 2500–2250 K & 350–0 & 115–0 & 115–0 & 40–0 \\ \hline \hline \end{tabular} Note: Estimates based on measurements performed in a small white room without daylight, with a spectrometer fixed at the average estimated lap position to measure horizontal task illuminance and at the estimated eye position to measure vertical illuminance. This table reports the beginning and end states of dynamic phases. Numbers have been rounded off for readability.  
\end{table} 
Table 2: Estimated illuminance and equivalent daylight (D65) illuminance (EDI) based on the task/lap and eye levels of the free-floor standing luminaire.