Make the button-shaped links actual links

"Web oficial" did nothing when clicked, and it was not alone: six places
wrapped `<pi-action-button>` in an `<a>`. That component renders a
`<button>`, so each one was a button inside a link -- invalid HTML, and
the button swallows the click. Besides "Web oficial" it covered Demo,
Repositorio, the contact CTA on every detail page, the 404's way home
and a call card's apply button.

They become one `app-link-button`, which renders a real anchor. The
click was only part of it: a link can also be opened in a new tab,
middle-clicked, copied, tabbed to and followed by a crawler.

Its look does not come from @pi/ui's button classes, and not for want of
trying: those rules are scoped to the element (`html button:not(…)` in
`_pi-button.scss`), so on an anchor they contribute nothing except
`pi-color__primary` -- a *text* colour, which painted the label violet on
a violet fill. The stylesheet reads the same `--pi-theme-button-*`
tokens the library reads instead, so a change of shell or theme still
moves these buttons and dark mode needs nothing of its own.

Verified: the anchor reports href, target and a real navigation to the
external site; no `<button>` inside an `<a>` remains on the page; and
the rendered pill matches the header's button in radius, gradient fill,
white text and weight, in both themes.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

landing/src/app/ui/call-card.ts

@@ -16,6 +16,7 @@ import type { Copy } from '../core/copy';
 import type { Locale } from '../core/api';
 import type { PublicCall } from '../core/api.types';
 import { TechnologyChip } from './technology-chip';
+import { LinkButton } from './link-button';
 
 @Component({
   selector: 'app-call-card',
@@ -32,6 +33,7 @@ import { TechnologyChip } from './technology-chip';
     PiTextColorDirective,
     PiTextWeightBoldDirective,
     TechnologyChip,
+    LinkButton,
   ],
   template: `
     <pi-card
@@ -96,15 +98,13 @@ import { TechnologyChip } from './technology-chip';
           <!-- To the call's own page and its form when it has one; to the
                landing's general form otherwise. -->
           @if (call().path; as path) {
-            <a class="landing-card__button-link" [href]="path">
-              <pi-action-button
+            <app-link-button
+              class="landing-card__button-link"
               size="small"
-                color="primary"
               appearance="outline"
-                [hasIcon]="true"
+              [href]="path"
               [text]="copy().labels.apply"
             />
-            </a>
           } @else {
             <pi-action-button
               size="small"

landing/src/app/ui/contact-cta.ts

@@ -4,11 +4,12 @@ import {
   computed,
   input,
 } from '@angular/core';
-import { PiActionButtonComponent, PiTextColorDirective } from '@pi/ui';
+import { PiTextColorDirective } from '@pi/ui';
 
 import type { Locale } from '../core/api';
 import type { Copy } from '../core/copy';
 import { homeHref } from '../core/routes';
+import { LinkButton } from './link-button';
 
 /**
  * "Shall we talk?" at the end of a page's side column, so no page is a dead
@@ -17,20 +18,18 @@ import { homeHref } from '../core/routes';
 @Component({
   selector: 'app-contact-cta',
   changeDetection: ChangeDetectionStrategy.OnPush,
-  imports: [PiActionButtonComponent, PiTextColorDirective],
+  imports: [PiTextColorDirective, LinkButton],
   template: `
     <div class="landing-card contact-cta">
       <h2 class="contact-cta__title">{{ copy().page.ctaTitle }}</h2>
       <p pi-color color="grey">{{ copy().page.ctaLead }}</p>
       <!-- An anchor around the library's button, which renders a <button>:
            a real link, so it works before hydration and opens in a new tab. -->
-      <a class="contact-cta__link" [href]="href()">
-        <pi-action-button
-          color="primary"
+      <app-link-button
+        class="contact-cta__link"
+        [href]="href()"
         [text]="copy().nav.contact"
-          [hasIcon]="true"
       />
-      </a>
     </div>
   `,
   styles: `

landing/src/app/ui/link-button.scss

@@ -0,0 +1,79 @@
+:host {
+  display: inline-flex;
+}
+
+// `@pi/ui` scopes its button rules to the element (`html button:not(…)` in
+// `_pi-button.scss`), so an anchor cannot inherit them. Every value below is
+// still the library's: these are the same `--pi-theme-button-*` custom
+// properties its own rules read, so switching shell or theme moves this button
+// too, and dark mode needs nothing of its own.
+.link-button {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  gap: 0.5rem;
+  min-width: 5.5rem;
+  border: none;
+  border-radius: var(--pi-theme-button-radius);
+  line-height: 100%;
+  text-decoration: none;
+  letter-spacing: var(--pi-theme-button-letter-spacing);
+  text-transform: var(--pi-theme-button-text-transform);
+  font-weight: var(--pi-theme-button-font-weight);
+  transition: var(--pi-theme-button-transition);
+  cursor: pointer;
+
+  svg {
+    flex: none;
+    width: 0.375rem;
+    height: 0.5625rem;
+  }
+
+  &:focus-visible {
+    outline: 2px solid var(--pi-color-primary);
+    outline-offset: 3px;
+  }
+}
+
+.link-button--medium,
+.link-button--large {
+  min-height: var(--pi-theme-button-height);
+  padding: var(--pi-spacing-xx-small) var(--pi-spacing-x-large);
+}
+
+.link-button--small {
+  min-width: 4.5rem;
+  padding: var(--pi-spacing-xxxx-small) var(--pi-spacing-medium);
+  font-size: 0.8125rem;
+}
+
+// Filled. The theme may inject a gradient over the flat colour, exactly as it
+// does for a real button.
+.link-button--fill {
+  color: var(--pi-color-white);
+  box-shadow: var(--pi-theme-button-shadow);
+
+  &.link-button--primary {
+    background-color: var(--pi-color-primary);
+    background-image: var(--pi-theme-button-fill-primary, none);
+  }
+
+  &.link-button--grey {
+    background-color: var(--pi-color-grey);
+  }
+}
+
+// Outline. The colour is the border and the text; the surface stays clear.
+.link-button--outline {
+  background: none;
+
+  &.link-button--primary {
+    border: 1px solid var(--pi-color-primary);
+    color: var(--pi-color-primary);
+  }
+
+  &.link-button--grey {
+    border: 1px solid var(--pi-color-grey-200);
+    color: var(--pi-color-grey);
+  }
+}

landing/src/app/ui/link-button.ts

@@ -0,0 +1,73 @@
+import { ChangeDetectionStrategy, Component, computed, input } from '@angular/core';
+
+/**
+ * A link that looks like the library's action button.
+ *
+ * `pi-action-button` renders a `<button>`, so wrapping one in an `<a>` puts a
+ * button inside a link: invalid HTML, and the button swallows the click, so
+ * nothing navigates. That is what stopped "Web oficial" working, and the same
+ * pattern sat in five other places.
+ *
+ * Making it an anchor is not only about the click. A real link can be opened
+ * in a new tab, middle-clicked, copied, reached by keyboard and followed by a
+ * crawler; a button can do none of that.
+ *
+ * The library's own button classes are deliberately NOT reused. Its rules are
+ * scoped to the element — `html button:not(…)` — so on an anchor they
+ * contribute nothing except `pi-color__primary`, which is a *text* colour and
+ * actively fights the white a filled button needs. The stylesheet beside this
+ * file reads the same `--pi-theme-button-*` tokens the library reads instead,
+ * so a change of shell or theme still reaches this button.
+ */
+type Size = 'small' | 'medium' | 'large';
+type Tone = 'primary' | 'grey';
+
+@Component({
+  selector: 'app-link-button',
+  changeDetection: ChangeDetectionStrategy.OnPush,
+  styleUrl: './link-button.scss',
+  template: `
+    <a
+      [class]="classes()"
+      [href]="href()"
+      [attr.target]="external() ? '_blank' : null"
+      [attr.rel]="external() ? 'noopener noreferrer' : null"
+    >
+      <span>{{ text() }}</span>
+
+      <svg
+        viewBox="0 0 6 9"
+        fill="none"
+        xmlns="http://www.w3.org/2000/svg"
+        aria-hidden="true"
+      >
+        <g>
+          <path
+            d="M1 1C4.5 4 5 4.38484 5 4.5C5 4.61516 4.5 5 1 8"
+            stroke="currentColor"
+            stroke-width="1"
+          />
+        </g>
+        <g>
+          <path d="M4.5 4.5H0" stroke="currentColor" stroke-width="1" />
+        </g>
+      </svg>
+    </a>
+  `,
+})
+export class LinkButton {
+  readonly href = input.required<string>();
+  readonly text = input.required<string>();
+  readonly size = input<Size>('medium');
+  readonly color = input<Tone>('primary');
+  readonly appearance = input<'fill' | 'outline'>('fill');
+  /** Opens in a new tab, for addresses that are not ours. */
+  readonly external = input(false);
+
+  protected readonly classes = computed(() => [
+    'link-button',
+    `link-button--${this.size()}`,
+    `link-button--${this.color()}`,
+    `link-button--${this.appearance()}`,
+  ]);
+}

landing/src/app/ui/not-found.ts

@@ -1,6 +1,6 @@
 import { ChangeDetectionStrategy, Component } from '@angular/core';
+import { LinkButton } from './link-button';
 import {
-  PiActionButtonComponent,
   PiIconComponent,
   PiTextColorDirective,
   PiTextMediumDirective,
@@ -26,12 +26,12 @@ import {
   changeDetection: ChangeDetectionStrategy.OnPush,
   imports: [
     PiIconComponent,
-    PiActionButtonComponent,
       PiTextXLargeDirective,
     PiTextMediumDirective,
     PiTextSmallDirective,
     PiTextColorDirective,
     PiTextWeightBoldDirective,
+    LinkButton,
   ],
   styleUrl: './not-found.scss',
   template: `
@@ -47,14 +47,12 @@ import {
           La dirección puede haber cambiado. Vuelve al inicio y sigue desde ahí.
         </p>
 
-        <a class="not-found__home" href="/">
-          <pi-action-button
+        <app-link-button
+          class="not-found__home"
           size="large"
-            color="primary"
+          href="/"
           text="Ir al inicio"
-            [hasIcon]="true"
         />
-        </a>
 
         <p s pi-color color="grey" class="not-found__note">
           Si has llegado desde un enlace nuestro, cuéntanoslo.

landing/src/app/ui/project-detail.ts

@@ -5,7 +5,6 @@ import {
   input,
 } from '@angular/core';
 import {
-  PiActionButtonComponent,
   PiAvatarComponent,
   PiChipComponent,
   PiChipStatusComponent,
@@ -21,6 +20,7 @@ import { ApiImage } from './api-image';
 import { ContactCta } from './contact-cta';
 import { PROJECT_STATUS_TONES } from './project-card';
 import { TechnologyChip } from './technology-chip';
+import { LinkButton } from './link-button';
 
 /**
  * A project on its own address: what it is, why it was built the way it was,
@@ -35,7 +35,6 @@ import { TechnologyChip } from './technology-chip';
   imports: [
     ApiImage,
     ContactCta,
-    PiActionButtonComponent,
       PiAvatarComponent,
     PiChipComponent,
     PiChipStatusComponent,
@@ -43,6 +42,7 @@ import { TechnologyChip } from './technology-chip';
     PiTextLargeDirective,
     PiTextWeightBoldDirective,
     TechnologyChip,
+    LinkButton,
   ],
   styleUrl: './project-detail.scss',
   template: `
@@ -92,23 +92,20 @@ import { TechnologyChip } from './technology-chip';
         @if (project().demo_url || repositoryUrl()) {
           <div class="content-hero__actions">
             @if (project().demo_url; as demo) {
-              <a [href]="demo" target="_blank" rel="noopener">
-                <pi-action-button
-                  color="primary"
+              <app-link-button
+                [href]="demo"
                 [text]="copy().labels.demo"
-                  [hasIcon]="true"
+                [external]="true"
               />
-              </a>
             }
             @if (repositoryUrl(); as repository) {
-              <a [href]="repository" target="_blank" rel="noopener">
-                <pi-action-button
-                  appearance="outline"
+              <app-link-button
                 color="grey"
+                appearance="outline"
+                [href]="repository"
                 [text]="copy().labels.repository"
-                  [hasIcon]="true"
+                [external]="true"
               />
-              </a>
             }
           </div>
         }

landing/src/app/ui/technology-detail.ts

@@ -5,7 +5,6 @@ import {
   input,
 } from '@angular/core';
 import {
-  PiActionButtonComponent,
   PiTextColorDirective,
   PiTextLargeDirective,
   PiTextWeightBoldDirective,
@@ -15,6 +14,7 @@ import type { Locale } from '../core/api';
 import type { PublicTechnology } from '../core/api.types';
 import type { Copy } from '../core/copy';
 import { listingPath } from '../core/routes';
+import { LinkButton } from './link-button';
 import { ApiImage } from './api-image';
 import { ContactCta } from './contact-cta';
 
@@ -36,10 +36,10 @@ import { ContactCta } from './contact-cta';
   imports: [
     ApiImage,
     ContactCta,
-    PiActionButtonComponent,
       PiTextColorDirective,
     PiTextLargeDirective,
     PiTextWeightBoldDirective,
+    LinkButton,
   ],
   styleUrl: './technology-detail.scss',
   template: `
@@ -75,14 +75,12 @@ import { ContactCta } from './contact-cta';
 
           @if (technology().website; as website) {
             <p class="content-hero__actions">
-              <a [href]="website" target="_blank" rel="noopener noreferrer">
-                <pi-action-button
+              <app-link-button
                 size="large"
-                  color="primary"
+                [href]="website"
                 [text]="copy().technology.website"
-                  [hasIcon]="true"
+                [external]="true"
               />
-              </a>
             </p>
           }
         </div>