convert .less files to .css and remove dependency

res/static/song.css

@@ -0,0 +1,125 @@
+@import "colors.css";
+
+table.chordedline {
+    border-spacing: 0px;
+    display: inline-block;
+}
+
+.chordedline td {
+    padding: 0px;
+}
+
+.chord {
+    font-style: italic;
+    color: var(--chord-color);
+    @media (prefers-color-scheme: dark) {
+        color: var(--chord-color-dark);
+    }
+}
+
+.song div {
+    margin: 0.5em 0;
+}
+
+div.chorus, p.chorus {
+    font-weight: bold;
+    border-left: var(--text-color) 2px solid;
+    @media (prefers-color-scheme: dark) {
+        border-left: var(--text-color-dark) 2px solid;
+    }
+    padding-left: 0.5em;
+    div {
+        padding-left: 0.5em;
+    }
+    table {
+        margin-left: 0;
+        padding-left: 0;
+        padding-right: 0;
+    }
+}
+
+.rrep {
+    background-image: url(repeat-sign.svg);
+    display: inline-block;
+    width: 1em;
+    height: 2em;
+    @media (prefers-color-scheme: dark) {
+        /* Black to white filter for svgs */
+        filter: invert(100%);
+    }
+}
+
+.lrep {
+    -moz-transform: scaleX(-1);
+    -o-transform: scaleX(-1);
+    -webkit-transform: scaleX(-1);
+    transform: scaleX(-1);
+    filter: FlipV;
+    -ms-filter: "FlipV";
+    .rrep();
+}
+
+.rep {
+    font-style: italic;
+}
+
+.echo {
+    font-style: italic;
+}
+
+button,
+select,
+input[type="button"] {
+    min-width: 2em;
+    min-height: 2em;
+    padding: .4em;
+    border-style: none;
+    border-radius: var(--border-radius);
+    color: var(--text-color);
+    background-color: var(--secondary-color);
+    @media (prefers-color-scheme: dark) {
+        color: var(--text-color-dark);
+        background-color: var(--secondary-color-dark);
+    }
+    &:hover,
+    &.pair-sub:hover ~ &.pair-sup {
+        background-color: var(--secondary-hover-color);
+        transition-duration: var(--transition-duration);
+        @media (prefers-color-scheme: dark) {
+            background-color: var(--secondary-hover-color-dark);
+        }
+    }
+}
+
+select.transposeSelect {
+    -webkit-appearance: none;
+    -moz-appearance: none;
+    font-weight: bold;
+    color: black;
+    @media (prefers-color-scheme: dark) {
+        color: var(--text-color-dark);
+    }
+}
+
+.flex-reverse {
+  display: inline-flex;
+  flex-direction: row-reverse;
+}
+
+.buttonpair.flex-reverse button.right,
+.buttonpair.flex-reverse button.left {
+    border: 1px solid var(--secondary-hover-color);
+    @media (prefers-color-scheme: dark) {
+        border-color: var(--secondary-hover-color-dark);
+    }
+}
+
+.buttonpair.flex-reverse button.right {
+  border-radius: 0px 10px 10px 0px;
+  border-width: 0 0 0 2px;
+}
+
+.buttonpair.flex-reverse button.left {
+  border-radius: 10px 0px 0px 10px;
+  border-width: 0 2px 0 0;
+}