Live home: nobody live right now says 'quiet now', not '-100%' in red (#166)

ddiff --git a/public/js/app-home.js b/public/js/app-home.js
iindex 74828803..8010a4ee 100644
---- a/public/js/app-home.js
++++ b/public/js/app-home.js
@@@ -224,6 +224,10 @@ function _baselineDeltaHTML(now, avg, peak, window = '24h') {
              : `Nothing in the last ${window}`;
          return `<span class="hero-stat-delta ${n > 0 ? 'is-up' : 'is-flat'}" title="${esc(tip)}"><b>${n > 0 ? 'first today' : 'quiet'}</b></span>`;
      }
++    // Nobody right now is not a crash: "-100%" in red read as broken on a quiet hour.
++    if (n === 0) {
++        return `<span class="hero-stat-delta is-flat" title="${esc(`Nobody right now · ${fmtAvg(a)} on average over the last ${window}`)}"><b>quiet now</b></span>`;
++    }
      const pct = Math.round(((n - a) / a) * 100);
      const bits = [`${_fmtCount(n)} right now`, `${fmtAvg(a)} on average over the last ${window}`];
      if (Number.isFinite(Number(peak))) bits.push(`peak ${_fmtCount(Math.round(peak))}`);
ddiff --git a/test/home-stat-quiet.test.js b/test/home-stat-quiet.test.js
nnew file mode 100644
iindex 00000000..bf349106
---- /dev/null
++++ b/test/home-stat-quiet.test.js
@@@ -0,0 +1,25 @@
++/**
++ * The home page's right-now counters (Live, Watching; public/js/app-home.js) compare with the last 24 hours. With
++ * nobody live they said "-100% vs 24h" in red, which read as broken on any quiet hour; zero now says "quiet now".
++ *
++ *   node test/home-stat-quiet.test.js
++ */
++'use strict';
++const assert = require('assert');
++const fs = require('fs');
++const path = require('path');
++
++const src = fs.readFileSync(path.join(__dirname, '..', 'public', 'js', 'app-home.js'), 'utf8');
++const start = src.indexOf('function _baselineDeltaHTML(');
++let i = src.indexOf('{', start), depth = 0;
++for (; i < src.length; i++) { if (src[i] === '{') depth++; else if (src[i] === '}' && --depth === 0) break; }
++// eslint-disable-next-line no-new-func
++const delta = new Function('_fmtCount', 'esc', `${src.slice(start, i + 1)}; return _baselineDeltaHTML;`)(String, (s) => String(s));
++
++assert.match(delta(0, 2.5, 4), /is-flat[^>]*><b>quiet now<\/b>/, 'zero now: quiet, not -100% in red');
++assert.ok(!/-100%/.test(delta(0, 2.5, 4)));
++assert.match(delta(3, 2, 4), /is-up[^>]*><b>\+50%<\/b>/, 'above average: up');
++assert.match(delta(1, 2, 4), /is-down[^>]*><b>-50%<\/b>/, 'below average but live: down');
++assert.match(delta(0, 0), /<b>quiet<\/b>/, 'nothing in 24 h: quiet');
++assert.match(delta(2, 0), /<b>first today<\/b>/);
++console.log('home stat quiet: all checks passed');