fix(web): replace emoji control icons with flat inline SVGs

The power, mute, shuffle, and repeat buttons used Unicode emoji (⏻ 🔇
🔀 🔁) which Android/mobile browsers render through the OS emoji font
with platform-specific colour styling, ignoring CSS color entirely.
This caused them to look like colourful emoji badges rather than flat
monochrome controls.

Replace each with an inline SVG using stroke/fill="currentColor" so
they inherit the button's text colour automatically — flat in both light
and dark mode, and correctly inverted when a button is in its active
(accent-background) state without any extra CSS filter.

The .ctrl-btn rule gains display:inline-flex + align-items:center to
vertically centre both text-character (⏮ ⏸ ⏭) and SVG content
consistently. The .volume-icon label in the volume row switches from
an emoji span to the same currentColor SVG at 16 px.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

pkg/service/soundtouchweb/static/css/app.css

@@ -274,7 +274,10 @@ img { display: block; max-width: 100%; }
     font-size: 1.1rem;
     padding: .25rem .4rem;
     border-radius: 4px;
-    line-height: 1;
+    line-height: 0;
+    display: inline-flex;
+    align-items: center;
+    justify-content: center;
     transition: opacity .15s;
 }
 .btn-icon:hover { opacity: .7; }
@@ -422,6 +425,10 @@ img { display: block; max-width: 100%; }
     border: 1px solid var(--border);
     background: var(--surface);
     color: var(--text);
+    display: inline-flex;
+    align-items: center;
+    justify-content: center;
+    line-height: 1;
     transition: background .12s;
 }
 .ctrl-btn:hover { background: var(--bg); }
@@ -429,7 +436,7 @@ img { display: block; max-width: 100%; }
 .ctrl-btn.active { background: var(--accent); color: var(--accent-fg); border-color: var(--accent); }
 
 .volume-row { display: flex; align-items: center; gap: .75rem; }
-.volume-icon { font-size: 1rem; }
+.volume-icon { display: flex; align-items: center; }
 .volume-slider { flex: 1; accent-color: var(--accent); }
 .volume-value { font-size: .8rem; color: var(--text-dim); min-width: 2.5ch; text-align: right; }
 

pkg/service/soundtouchweb/static/js/app.js

@@ -31,7 +31,12 @@ function DeviceDetail({ deviceId, devices, onBack }) {
         <div class="device-detail">
             <div class="page-header">
                 <button class="back-btn" onClick=${onBack}>← Back</button>
-                <button class="btn-icon" onClick=${() => api.power(deviceId)} title="Power">⏻</button>
+                <button class="btn-icon" onClick=${() => api.power(deviceId)} title="Power">
+                    <svg width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" aria-hidden="true">
+                        <path d="M12 2v8" />
+                        <path d="M18.36 6.64a9 9 0 1 1-12.73 0" />
+                    </svg>
+                </button>
             </div>
             <${NowPlaying} nowPlaying=${device.status?.nowPlaying} deviceId=${deviceId} presets=${device.status?.presets} />
             <${Controls} deviceId=${deviceId} status=${device.status} />

pkg/service/soundtouchweb/static/js/components/Controls.js

@@ -5,6 +5,44 @@ import { api } from '../api.js';
 
 const html = htm.bind(h);
 
+// Flat SVG icons using stroke/fill="currentColor" so they automatically
+// follow the button's text colour in light mode, dark mode, and in the
+// accent-inverted active state — no CSS filter needed.
+
+function IconVolume({ muted = false, size = 20 }) {
+    if (muted) {
+        return html`<svg width=${size} height=${size} viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true">
+            <polygon points="11 5 6 9 2 9 2 15 6 15 11 19 11 5"/>
+            <line x1="23" y1="9" x2="17" y2="15"/>
+            <line x1="17" y1="9" x2="23" y2="15"/>
+        </svg>`;
+    }
+    return html`<svg width=${size} height=${size} viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true">
+        <polygon points="11 5 6 9 2 9 2 15 6 15 11 19 11 5"/>
+        <path d="M15.54 8.46a5 5 0 0 1 0 7.07"/>
+    </svg>`;
+}
+
+function IconShuffle() {
+    return html`<svg width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true">
+        <polyline points="16 3 21 3 21 8"/>
+        <line x1="4" y1="20" x2="21" y2="3"/>
+        <polyline points="21 16 21 21 16 21"/>
+        <line x1="15" y1="15" x2="21" y2="21"/>
+        <line x1="4" y1="4" x2="9" y2="9"/>
+    </svg>`;
+}
+
+function IconRepeat({ one = false }) {
+    return html`<svg width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true">
+        <polyline points="17 1 21 5 17 9"/>
+        <path d="M3 11V9a4 4 0 0 1 4-4h14"/>
+        <polyline points="7 23 3 19 7 15"/>
+        <path d="M21 13v2a4 4 0 0 1-4 4H3"/>
+        ${one && html`<text x="12" y="15" text-anchor="middle" font-size="8" font-weight="bold" stroke="none" fill="currentColor" font-family="sans-serif">1</text>`}
+    </svg>`;
+}
+
 export function Controls({ deviceId, status }) {
     const np = status?.nowPlaying;
     const isPlaying = np?.PlayStatus === 'PLAY_STATE';
@@ -45,8 +83,6 @@ export function Controls({ deviceId, status }) {
         else send('REPEAT_OFF');
     }
 
-    const repeatIcon = repeat === 'REPEAT_ONE' ? '🔂' : '🔁';
-
     return html`
         <div class="controls">
             <div class="transport">
@@ -56,13 +92,17 @@ export function Controls({ deviceId, status }) {
                 </button>
                 <button class="ctrl-btn" onClick=${() => send('NEXT_TRACK')} title="Next">⏭</button>
                 <button class="ctrl-btn ${isMuted ? 'active' : ''}" onClick=${() => send('MUTE')} title="Mute">
-                    ${isMuted ? '🔇' : '🔊'}
+                    ${IconVolume({ muted: isMuted })}
+                </button>
+                <button class="ctrl-btn ${shuffle === 'SHUFFLE_ON' ? 'active' : ''}" onClick=${toggleShuffle} title="Shuffle">
+                    ${IconShuffle()}
+                </button>
+                <button class="ctrl-btn ${repeat !== 'REPEAT_OFF' ? 'active' : ''}" onClick=${cycleRepeat} title=${repeat === 'REPEAT_ONE' ? 'Repeat one' : repeat === 'REPEAT_ALL' ? 'Repeat all' : 'Repeat'}>
+                    ${IconRepeat({ one: repeat === 'REPEAT_ONE' })}
                 </button>
-                <button class="ctrl-btn ${shuffle === 'SHUFFLE_ON' ? 'active' : ''}" onClick=${toggleShuffle} title="Shuffle">🔀</button>
-                <button class="ctrl-btn ${repeat !== 'REPEAT_OFF' ? 'active' : ''}" onClick=${cycleRepeat} title="Repeat">${repeatIcon}</button>
             </div>
             <div class="volume-row">
-                <span class="volume-icon">🔈</span>
+                <span class="volume-icon">${IconVolume({ size: 16 })}</span>
                 <input type="range" class="volume-slider" min="0" max="100"
                     value=${localVolume} onInput=${onVolumeChange} />
                 <span class="volume-value">${localVolume}</span>
@@ -77,4 +117,4 @@ export function Controls({ deviceId, status }) {
             `}
         </div>
     `;
-}
+}