feat: VivesPOS landing on Winter CMS 1.2 — theme + plugin + Dockerfile

- Base: wintercms/winter branch 1.2 (full framework)
- Theme vivespos: Canvas 7 + Bootstrap 5 CDN, custom CSS
- Layout: deferred GTM/GA4 tracking, JSON-LD SoftwareApplication
- Partials: hero (offline-first), features, modes (offline/nube toggle),
  screenshots, pricing (3 planes), comparison, FAQ, CTA
- Plugin VivesPOS.Site with ContactForm
- Dockerfile: PHP 8.2 Apache, port 80, healthcheck
- Added winter/wn-pages, blog, sitemap, seo plugins
- Active theme set to vivespos

modules/system/assets/ui/less/global.mixins.utility.less

@@ -0,0 +1,134 @@
+// Utilities
+// -------------------------
+
+// Clearfix
+// Source: http://nicolasgallagher.com/micro-clearfix-hack/
+//
+// For modern browsers
+// 1. The space content is one way to avoid an Opera bug when the
+//    contenteditable attribute is included anywhere else in the document.
+//    Otherwise it causes space to appear at the top and bottom of elements
+//    that are clearfixed.
+// 2. The use of `table` rather than `block` is only necessary if using
+//    `:before` to contain the top-margins of child elements.
+.clearfix() {
+    &:before,
+    &:after {
+        content: " "; // 1
+        display: table; // 2
+    }
+    &:after {
+        clear: both;
+    }
+}
+
+// WebKit-style focus
+.tab-focus() {
+    // Default
+    outline: thin dotted;
+    outline-offset: 0px;
+
+    // Firefox
+    outline: 4px auto Highlight;
+    // WebKit
+    outline: 4px auto -webkit-focus-ring-color;
+}
+
+// Center-align a block level element
+.center-block() {
+    display: block;
+    margin-left: auto;
+    margin-right: auto;
+}
+
+// Sizing shortcuts
+.size(@width; @height) {
+    width: @width;
+    height: @height;
+}
+.square(@size) {
+    .size(@size; @size);
+}
+
+// Placeholder text
+.placeholder(@color: @input-color-placeholder) {
+    &::-moz-placeholder           { color: @color;   // Firefox
+                                                                    opacity: 1; } // See https://github.com/twbs/bootstrap/pull/11526
+    &:-ms-input-placeholder       { color: @color; } // Internet Explorer 10+
+    &::-webkit-input-placeholder  { color: @color; } // Safari and Chrome
+}
+
+// Text overflow
+// Requires inline-block or block for proper styling
+.text-overflow() {
+    overflow: hidden;
+    text-overflow: ellipsis;
+    white-space: nowrap;
+}
+
+// CSS image replacement
+//
+// Heads up! v3 launched with with only `.hide-text()`, but per our pattern for
+// mixins being reused as classes with the same name, this doesn't hold up. As
+// of v3.0.1 we have added `.text-hide()` and deprecated `.hide-text()`. Note
+// that we cannot chain the mixins together in Less, so they are repeated.
+//
+// Source: https://github.com/h5bp/html5-boilerplate/commit/aa0396eae757
+
+// Deprecated as of v3.0.1 (will be removed in v4)
+.hide-text() {
+    font: ~"0/0" a;
+    color: transparent;
+    text-shadow: none;
+    background-color: transparent;
+    border: 0;
+}
+// New mixin to use as of v3.0.1
+.text-hide() {
+    .hide-text();
+}
+
+// Retina images
+//
+// Short retina mixin for setting background-image and -size
+
+.img-retina(@file-1x; @file-2x; @width-1x; @height-1x) {
+    background-image: url("@{file-1x}");
+
+    @media
+    only screen and (-webkit-min-device-pixel-ratio: 2),
+    only screen and (   min--moz-device-pixel-ratio: 2),
+    only screen and (     -o-min-device-pixel-ratio: 2/1),
+    only screen and (        min-device-pixel-ratio: 2),
+    only screen and (                min-resolution: 192dpi),
+    only screen and (                min-resolution: 2dppx) {
+        background-image: url("@{file-2x}");
+        background-size: @width-1x @height-1x;
+    }
+}
+
+
+// Responsive image
+//
+// Keep images from scaling beyond the width of their parents.
+
+.img-responsive(@display: block;) {
+    display: @display;
+    max-width: 100%; // Part 1: Set a maximum relative to the parent
+    height: auto; // Part 2: Scale the height according to the width, otherwise you get stretching
+}
+
+// Responsive utilities
+// -------------------------
+// More easily include all the states for responsive-utilities.less.
+.responsive-visibility() {
+    display: block !important;
+    table&  { display: table; }
+    tr&     { display: table-row !important; }
+    th&,
+    td&     { display: table-cell !important; }
+}
+
+.responsive-invisibility() {
+    display: none !important;
+}