{#- chirp-ui: ASCII Border
    Box-drawing character frame around content. Pure CSS, no images.

    Usage:
        from "chirpui/ascii_border.html" import ascii_border

        {% call ascii_border() %}
            <p>Content in a terminal-style frame</p>
        {% end %}

        {% call ascii_border(variant="double") %}
            <h2>Double-line frame</h2>
        {% end %}

        {% call ascii_border(variant="rounded", glyph="✦") %}
            <p>Rounded corners with a glyph accent</p>
        {% end %}

    Variants: single (default), double, rounded, heavy
-#}

{% def ascii_border(variant="", glyph="", cls="") %}
{% set variant = variant | validate_variant(("", "single", "double", "rounded", "heavy"), "") %}
{% set variant_class = " chirpui-ascii-border--" ~ variant if variant else "" %}
{# Box-drawing character sets — defaults for single/unset #}
{% set tl = "╔" if variant == "double" else "╭" if variant == "rounded" else "┏" if variant == "heavy" else "┌" %}
{% set h  = "═" if variant == "double" else "─" if variant == "rounded" else "━" if variant == "heavy" else "─" %}
{% set tr = "╗" if variant == "double" else "╮" if variant == "rounded" else "┓" if variant == "heavy" else "┐" %}
{% set v  = "║" if variant == "double" else "│" if variant == "rounded" else "┃" if variant == "heavy" else "│" %}
{% set bl = "╚" if variant == "double" else "╰" if variant == "rounded" else "┗" if variant == "heavy" else "└" %}
{% set br = "╝" if variant == "double" else "╯" if variant == "rounded" else "┛" if variant == "heavy" else "┘" %}
<div class="chirpui-ascii-border{{ variant_class }}{{ " " ~ cls if cls else "" }}">
    <div class="chirpui-ascii-border__top" aria-hidden="true"><span class="chirpui-ascii-border__corner">{{ tl }}</span><span class="chirpui-ascii-border__line">{% if glyph %}{{ h }}{{ h }} {{ glyph }} {{ h }}{{ h }}{% end %}</span><span class="chirpui-ascii-border__corner">{{ tr }}</span></div>
    <div class="chirpui-ascii-border__mid">
        <span class="chirpui-ascii-border__side" aria-hidden="true">{{ v }}</span>
        <div class="chirpui-ascii-border__content">
            {% slot %}
        </div>
        <span class="chirpui-ascii-border__side" aria-hidden="true">{{ v }}</span>
    </div>
    <div class="chirpui-ascii-border__bottom" aria-hidden="true"><span class="chirpui-ascii-border__corner">{{ bl }}</span><span class="chirpui-ascii-border__line"></span><span class="chirpui-ascii-border__corner">{{ br }}</span></div>
</div>
{% end %}