/* ==========================================================================
   Source editor
   A transparent <textarea> sits on top of a highlighted backdrop that
   mirrors its text line by line (line numbers, syntax colours, current
   line). Both layers must share exactly the same text metrics.
   ========================================================================== */

.code-editor {
    --digits: 2;
    --gutter: calc(var(--digits) * 1ch + 38px);
    --pad-right: 20px;
    --scrollbar: 0px;
    position: relative;
    flex: 1;
    min-height: 0;
    overflow: hidden;
}

.code-backdrop,
.code-input {
    position: absolute;
    inset: 0;
    margin: 0;
    border: 0;
    padding-top: 14px;
    padding-bottom: 28px;
    font-family: var(--font-mono);
    font-size: var(--editor-font-size);
    font-weight: 400;
    line-height: var(--editor-line-height);
    letter-spacing: normal;
    word-spacing: normal;
    tab-size: 4;
    white-space: pre-wrap;
    overflow-wrap: break-word;
    word-break: normal;
    text-align: left;
    text-indent: 0;
    text-transform: none;
    font-kerning: none;
    font-variant-ligatures: none;
    font-feature-settings: "liga" 0, "calt" 0;
    /* Never fake bold/italic: synthetic glyphs can change advance widths
       and push the highlighted text out of line with the caret. */
    font-synthesis: none;
    /* Chrome compresses full-width CJK punctuation such as "）、", but where
       a line wraps it does so differently in a textarea than in normal
       text, so a long line could wrap one row later in one layer and every
       line below would be off by a row. Keep both layers untouched. */
    text-spacing-trim: space-all;
    text-autospace: no-autospace;
}

.code-backdrop {
    padding-left: 0;
    padding-right: 0;
    /* Extra room so the backdrop can always scroll as far as the textarea */
    padding-bottom: calc(28px + 50vh);
    overflow: hidden;
    pointer-events: none;
    color: var(--text-control);
    counter-reset: line;
}

.code-input {
    width: 100%;
    height: 100%;
    padding-left: var(--gutter);
    padding-right: var(--pad-right);
    overflow-x: hidden;
    overflow-y: auto;
    resize: none;
    outline: none;
    background: transparent;
    color: transparent;
    caret-color: var(--text);
    -webkit-text-fill-color: transparent;
}

.code-input::placeholder {
    color: var(--faint);
    -webkit-text-fill-color: var(--faint);
}

.code-input::selection {
    background: var(--selection);
    color: transparent;
}

.code-input:focus-visible {
    outline: none;
}

.ln {
    position: relative;
    padding-left: var(--gutter);
    padding-right: calc(var(--pad-right) + var(--scrollbar));
    counter-increment: line;
}

.ln::before {
    content: counter(line);
    position: absolute;
    top: 0;
    left: 0;
    width: var(--gutter);
    padding-right: 18px;
    box-sizing: border-box;
    text-align: right;
    color: var(--faint);
    font-weight: 400;
    font-style: normal;
}

.code-editor:focus-within .ln.is-current {
    background: var(--accent-soft);
}

.code-editor:focus-within .ln.is-current::before {
    color: var(--text-control);
}

/* iOS Safari indents textarea text by 3px */
.is-ios .ln {
    padding-left: calc(var(--gutter) + 3px);
    padding-right: calc(var(--pad-right) + var(--scrollbar) + 3px);
}

/* --- Markdown syntax colours -------------------------------------------- */

.t-mark {
    color: var(--faint);
}

.t-heading {
    font-weight: 500;
    color: var(--text-strong);
}

.t-bold {
    font-weight: 600;
}

.t-italic {
    font-style: italic;
}

.t-strike {
    text-decoration: line-through;
}

.t-hl {
    background: var(--mark-bg);
    color: var(--mark-fg);
    border-radius: 3px;
}

.t-code,
.t-lang,
.t-string {
    color: var(--warm);
}

.t-math,
.t-accent {
    color: var(--accent);
}

.t-url {
    color: var(--muted);
    text-decoration: underline;
    text-decoration-color: var(--dot);
    text-underline-offset: 2px;
}

.t-comment {
    color: var(--muted);
}

.t-html {
    color: var(--muted);
}