Ghost/ghost/admin/app/components/modal-install-theme.hbs

<div class="theme-validation-container" {{did-update this.reset @model}}>
    <header class="modal-header" data-test-modal="install-theme">
        <h1>
            {{#if this.installSuccess}}
                {{#if this.hasWarningsOrErrors}}
                    Install successful with {{#if this.validationErrors}}errors{{else}}warnings{{/if}}
                {{else}}
                    Install successful!
                {{/if}}
            {{else if this.hasWarningsOrErrors}}
                Invalid theme
            {{else}}
                Install theme
            {{/if}}
        </h1>
    </header>
    <button type="button" class="close" title="Close" {{on "click" this.close}}>{{svg-jar "close"}}<span class="hidden">Close</span></button>

    <div class="modal-body">
        {{#if this.isReady}}
            <p>
                Are you sure you want to install <strong>{{this.themeName}}</strong> from
                <a href="https://github.com/{{this.model.ref}}" target="_blank" rel="noopener noreferrer">https://github.com/{{this.model.ref}}</a>?
            </p>
            {{#if this.willOverwriteExisting}}
                <p>
                    This will overwrite your existing version of {{this.themeName}}{{if this.willOverwriteExisting.active " which is your active theme"}}.
                    Any custom changes will be lost.
                </p>
            {{/if}}
        {{/if}}

        {{#if this.willOverwriteDefault}}
            <p>
                Sorry, the default Casper theme cannot be overwritten.<br>
                If you wish to make changes please download the theme and upload a renamed zip file.
            </p>
        {{/if}}

        {{#if this.installSuccess}}
            {{#if this.hasWarningsOrErrors}}
                <p>
                    The theme <strong>"{{this.themeName}}"</strong> was installed successfully but we detected some {{if this.validationErrors "errors" "warnings"}}.
                    {{#unless this.theme.active}}
                        You are still able to activate and use the theme but it is recommended to fix these {{if this.validationErrors "errors" "warnings"}} before you do so.
                    {{/unless}}
                </p>
            {{else}}
                {{!-- Installed with no errors --}}
                <p>The theme <strong>"{{this.themeName}}"</strong> was installed successfully. {{unless this.theme.active "Do you want to activate it now?"}}</p>
            {{/if}}
        {{/if}}

        {{#if this.installError}}
            {{!-- Outright failure - not found, not a theme, server error, etc --}}
            <p>{{this.themeName}} failed to install.</p>
            <p class="error"><strong class="response">{{this.installError}}</strong></p>
        {{/if}}

        {{#if this.installFailure}}
            {{!-- Invalid theme --}}
            <p>This theme is invalid and cannot be activated. Contact the theme developer.</p>
        {{/if}}

        {{#if this.fatalValidationErrors}}
            <div>
                <h2 class="mb0 mt4 f5 fw6">Fatal Errors</h2>
                <p class="mb2">Must-fix to activate theme</p>
            </div>

            <ul class="pa0">
            {{#each this.fatalValidationErrors as |error|}}
                <li class="theme-validation-item theme-fatal-error">
                    <GhThemeErrorLi @error={{error}} />
                </li>
            {{/each}}
            </ul>
        {{/if}}

        {{#if this.validationErrors}}
            <div>
                <h2 class="mb0 mt4 f5 fw6">Errors</h2>
                <p class="mb2">Highly recommended to fix, functionality <strong>could</strong> be restricted</p>
            </div>
            <ul class="pa0">
            {{#each this.validationErrors as |error|}}
                <li class="theme-validation-item theme-error">
                    <GhThemeErrorLi @error={{error}} />
                </li>
            {{/each}}
            </ul>
        {{/if}}

        {{#if this.validationWarnings}}
            <div>
                <h2 class="mb0 mt4 f5 fw6">Warnings</h2>
            </div>
            <ul class="pa0">
            {{#each this.validationWarnings as |error|}}
                <li class="theme-validation-item theme-warning">
                    <GhThemeErrorLi @error={{error}} />
                </li>
            {{/each}}
            </ul>
        {{/if}}
    </div>

    <div class="modal-footer">
        <div class="flex items-center justify-between {{if this.hasActionButton "flex-auto"}}">
            <button type="button" class="gh-btn" {{on "click" this.close}} data-test-button="cancel">
                <span>{{#if (or this.installSuccess this.installFailure)}}Close{{else}}Cancel{{/if}}</span>
            </button>

            {{#if this.hasActionButton}}
                <div class="flex items-center">
                    {{#if this.shouldShowInstall}}
                        <GhTaskButton
                            @task={{this.installTask}}
                            @type="button"
                            @class="gh-btn gh-btn-icon gh-btn-green"
                            @buttonText={{if this.willOverwriteExisting "Overwrite" "Install"}}
                            @runningText="Installing"
                            @successText="Installed"
                            data-test-button="install"
                        />
                    {{/if}}

                    {{#if this.shouldShowActivate}}
                        <GhTaskButton
                            @task={{this.activateTask}}
                            @type="button"
                            @class="gh-btn gh-btn-icon gh-btn-green"
                            @buttonText="Activate"
                            @runningText="Activating"
                            data-test-button="activate"
                        />
                    {{/if}}
                </div>
            {{/if}}
        </div>
    </div>
</div>