polish: icon sizing hardened for cross-browser (review I-1/M2/M3/M4)

- .sf-tp-icon CSS width/height (Safari doesn't support var() in SVG
  presentation attributes); --sm variant class replaces size= call sites
- search icon centered via translateY, decoupled from input height
- bare-arrow test: full charset (→←↗↘⌕▾) + line-level › whitelist
- new test: site.html tp_arrow must stay in sync with macro library path

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

themes/trade-pro/pro.html

@@ -16,7 +16,7 @@
    keeping all 7 default sections so only the labels change, never coverage. #}
 {% set tp_nav=[{'title':'Home','route':'/'},{'title':'Products','route':'/products/'},{'title':'Brands','route':'/brands/'},{'title':'News','route':'/news/'},{'title':'Cases','route':'/cases/'},{'title':'About','route':'/about/'},{'title':'Contact','route':'/contact/'}] if tp_needs_en_nav else nav %}
 {% if chrome_is_custom %}<div class="pro-utility"{% if not chrome.header.show_announcement %} hidden{% endif %}><div class="pro-wrap"><span>{{ chrome.header.announcement }}</span><span>{{ site.tagline or site.name }}</span></div></div>{% else %}<div class="pro-utility"><div class="pro-wrap"><span>GLOBAL SOURCING · QUALITY · DELIVERY</span><span>INTERNATIONAL B2B SOLUTIONS</span></div></div>{% endif %}
-<header class="sf-site-head pro-header"><div class="pro-wrap pro-head-inner"><a class="pro-logo" href="/" aria-label="{{site.name}} home">{% if safe_image(site.logo) %}<img class="pro-brand-logo" src="{{safe_image(site.logo)}}" alt="{{site.name}} Logo">{% else %}<span class="pro-logo-symbol">▣</span>{% endif %}<span class="pro-logo-name">{{site.name}}<small> GLOBAL B2B</small></span></a><button class="pro-mobile-toggle" type="button" data-pro-menu aria-controls="pro-navigation" aria-expanded="false" aria-label="Open navigation">☰</button><nav id="pro-navigation" class="pro-navigation" aria-label="Main navigation">{% for link in tp_nav %}{% if link.children %}<div class="pro-nav-group"><a href="{{link.route}}">{{link.title}}</a><button type="button" class="pro-nav-disclose" aria-expanded="false" aria-label="Expand {{link.title}} submenu">{{ icon('chevron-down', size='var(--sf-tp-icon-size-sm, 16px)') }}</button><div class="pro-nav-children" hidden>{% for child in link.children %}<a href="{{child.route}}">{{child.title}}</a>{% for leaf in child.children %}<a class="pro-nav-leaf" href="{{leaf.route}}">— {{leaf.title}}</a>{% endfor %}{% endfor %}</div></div>{% else %}<a href="{{link.route}}">{{link.title}}</a>{% endif %}{% endfor %}{% if chrome.header.show_search %}<a class="pro-search-link" href="/search/">Search {{ icon('search', size='var(--sf-tp-icon-size-sm, 16px)') }}</a>{% endif %}</nav><button class="pro-catalog-toggle" type="button" data-pro-catalog aria-controls="pro-mega-content" aria-expanded="false">Products {{ icon('chevron-down', size='var(--sf-tp-icon-size-sm, 16px)') }}</button>{% if chrome_is_custom %}{% if chrome.header.show_cta %}<a href="{{chrome.header.cta_href}}" class="sf-tp-btn pro-header-cta">{{chrome.header.cta_text}} <span>{{ icon('arrow-right') }}</span></a>{% endif %}{% else %}<a href="/contact/" class="sf-tp-btn pro-header-cta">Request a Quote <span>{{ icon('arrow-right') }}</span></a>{% endif %}</div>{% if categories %}<div class="pro-mega pro-wrap" data-pro-mega id="pro-mega-content" hidden><span>Product categories</span><div>{% for cat in categories[:12] %}<a href="{{cat.url}}">{{cat.name}} {{ icon('arrow-right') }}</a>{% endfor %}</div></div>{% endif %}</header>
+<header class="sf-site-head pro-header"><div class="pro-wrap pro-head-inner"><a class="pro-logo" href="/" aria-label="{{site.name}} home">{% if safe_image(site.logo) %}<img class="pro-brand-logo" src="{{safe_image(site.logo)}}" alt="{{site.name}} Logo">{% else %}<span class="pro-logo-symbol">▣</span>{% endif %}<span class="pro-logo-name">{{site.name}}<small> GLOBAL B2B</small></span></a><button class="pro-mobile-toggle" type="button" data-pro-menu aria-controls="pro-navigation" aria-expanded="false" aria-label="Open navigation">☰</button><nav id="pro-navigation" class="pro-navigation" aria-label="Main navigation">{% for link in tp_nav %}{% if link.children %}<div class="pro-nav-group"><a href="{{link.route}}">{{link.title}}</a><button type="button" class="pro-nav-disclose" aria-expanded="false" aria-label="Expand {{link.title}} submenu">{{ icon('chevron-down', cls='sf-tp-icon--sm') }}</button><div class="pro-nav-children" hidden>{% for child in link.children %}<a href="{{child.route}}">{{child.title}}</a>{% for leaf in child.children %}<a class="pro-nav-leaf" href="{{leaf.route}}">— {{leaf.title}}</a>{% endfor %}{% endfor %}</div></div>{% else %}<a href="{{link.route}}">{{link.title}}</a>{% endif %}{% endfor %}{% if chrome.header.show_search %}<a class="pro-search-link" href="/search/">Search {{ icon('search', cls='sf-tp-icon--sm') }}</a>{% endif %}</nav><button class="pro-catalog-toggle" type="button" data-pro-catalog aria-controls="pro-mega-content" aria-expanded="false">Products {{ icon('chevron-down', cls='sf-tp-icon--sm') }}</button>{% if chrome_is_custom %}{% if chrome.header.show_cta %}<a href="{{chrome.header.cta_href}}" class="sf-tp-btn pro-header-cta">{{chrome.header.cta_text}} <span>{{ icon('arrow-right') }}</span></a>{% endif %}{% else %}<a href="/contact/" class="sf-tp-btn pro-header-cta">Request a Quote <span>{{ icon('arrow-right') }}</span></a>{% endif %}</div>{% if categories %}<div class="pro-mega pro-wrap" data-pro-mega id="pro-mega-content" hidden><span>Product categories</span><div>{% for cat in categories[:12] %}<a href="{{cat.url}}">{{cat.name}} {{ icon('arrow-right') }}</a>{% endfor %}</div></div>{% endif %}</header>
 {% if not designer_replace %}{% include 'trade-pro/pages/' ~ kind ~ '.html' %}{% endif %}
 
 {% if has_custom and kind!='notfound' %}<main id="main-content" class="sf-canvas pro-custom-content">{{custom_blocks}}</main>{% else %}<main id="main-content" class="sf-canvas pro-custom-content" aria-hidden="true"></main>{% endif %}