Wow. This is some seriously cool work. Thanks so much for sharing. I have most of it figured out and got those icons as they look great. I am having trouble getting the CSS applied to the svg icons.
I figured out which icons I need and changed their ids accordingly. Then I ran them through spritesh to merge them into button.svg. They all appear, but the colours are off…as in not being overridden by the CSS.
I gave it a good try, but can’t get this part figured out. Help would be appreciated 
From theme.css
}
.section .icon.off svg {
fill: #565f58;
}
.section .icon.on svg {
fill: #26bf75;
}
(I played around with stroke to get the grey (the icons were originally showing up as black) since I couldn’t override and I also got rid of fill=“none”, but no dice. I also tried referencing the css from within the svg, but that didn’t help. It is weird…the circle of the thermometer is green, suggesting that the css is working, but the rest is grey.
<?xml-stylesheet type="text/css" href="theme.css" ?>
<g id="thermometer1">
<g>
<line stroke="#565f58" stroke-width="2" stroke-linejoin="round" stroke-miterlimit="10" x1="24" y1="24" x2="24" y2="35"/>
<path fill="none" stroke="#565f58" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" stroke-miterlimit="10" d="
M28,31.1V7c0-2.2-1.8-4-4-4h0c-2.2,0-4,1.8-4,4v24.1c-2.7,1.6-4.4,4.7-3.9,8.2c0.5,3.5,3.5,6.3,7,6.7c4.8,0.5,8.9-3.2,8.9-7.9
C32,35,30.4,32.5,28,31.1z"/>
<circle cx="24" cy="38" r="5"/>
<line stroke="#565f58" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" stroke-miterlimit="10" x1="33" y1="6" x2="35" y2="6"/>
<line stroke="#565f58" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" stroke-miterlimit="10" x1="33" y1="11" x2="35" y2="11"/>
<line stroke="#565f58" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" stroke-miterlimit="10" x1="33" y1="16" x2="35" y2="16"/>
<line stroke="#565f58" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" stroke-miterlimit="10" x1="33" y1="21" x2="35" y2="21"/>
</g>
And from the dashboard
<div class="section">
<div class="bigDash">
<div class="description">Outdoor</div>
<div class="top">
<div class="icon on"><svg viewBox="0 0 48 48"><use xlink:href="/static/button.svg#thermometer1"></use></svg></div>
<div class="value">
<div class="main">{{itemValue('Outdoor_Temp_Back') | number:1}}</div>
<div class="sub">°C</div>
</div>
</div>
<div class="bottom">
<div class="icon off"><svg viewBox="0 0 48 48"><use xlink:href="/static/button.svg#thermometer1"></use></svg></div>
<div class="value">feels like {{itemValue('xxxx') | number:0}} °C</div>