/* ===== LaTeX to Video — front-end styles ===== */
.ltv-app {
    --ltv-bg: #f8fafc;
    --ltv-panel: #ffffff;
    --ltv-border: #e2e8f0;
    --ltv-ink: #0f172a;
    --ltv-muted: #64748b;
    --ltv-primary: #2563eb;
    --ltv-accent: #0ea5e9;
    --ltv-green: #059669;
    max-width: 1100px;
    margin: 24px auto;
    padding: 24px;
    background: var(--ltv-bg);
    border: 1px solid var(--ltv-border);
    border-radius: 16px;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    color: var(--ltv-ink);
    box-sizing: border-box;
}
.ltv-app *, .ltv-app *::before, .ltv-app *::after { box-sizing: border-box; }

.ltv-header { text-align: center; margin-bottom: 20px; }
.ltv-title { margin: 0; font-size: 28px; font-weight: 800; letter-spacing: -.5px; }
.ltv-sub { margin: 6px 0 0; color: var(--ltv-muted); font-size: 14px; }

.ltv-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}
@media (max-width: 820px) { .ltv-grid { grid-template-columns: 1fr; } }

.ltv-panel {
    background: var(--ltv-panel);
    border: 1px solid var(--ltv-border);
    border-radius: 12px;
    padding: 16px;
}
.ltv-label { display: block; font-weight: 700; font-size: 13px; margin-bottom: 8px; text-transform: uppercase; letter-spacing: .5px; color: var(--ltv-muted); }

.ltv-textarea {
    width: 100%;
    min-height: 180px;
    resize: vertical;
    padding: 12px;
    font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
    font-size: 14px;
    line-height: 1.5;
    border: 1px solid var(--ltv-border);
    border-radius: 8px;
    background: #fbfdff;
    color: var(--ltv-ink);
}
.ltv-textarea:focus { outline: 2px solid var(--ltv-primary); border-color: transparent; }

.ltv-controls { margin-top: 14px; display: flex; flex-direction: column; gap: 12px; }
.ltv-control label { font-size: 13px; font-weight: 600; display: block; margin-bottom: 4px; }
.ltv-control input[type="range"] { width: 100%; accent-color: var(--ltv-primary); }
.ltv-control-inline { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.ltv-control-inline label { margin: 0; }
.ltv-control-inline input[type="color"] { width: 38px; height: 32px; border: 1px solid var(--ltv-border); border-radius: 6px; padding: 0; cursor: pointer; }

.ltv-btn-row { margin-top: 16px; display: flex; gap: 10px; flex-wrap: wrap; }
.ltv-btn {
    flex: 1;
    min-width: 120px;
    text-align: center;
    padding: 11px 18px;
    border: none;
    border-radius: 8px;
    font-size: 15px;
    font-weight: 700;
    cursor: pointer;
    transition: transform .08s ease, opacity .15s ease;
    text-decoration: none;
    display: inline-block;
}
.ltv-btn:active { transform: translateY(1px); }
.ltv-btn:disabled { opacity: .55; cursor: not-allowed; }
.ltv-btn-primary { background: var(--ltv-primary); color: #fff; }
.ltv-btn-accent { background: var(--ltv-accent); color: #fff; }
.ltv-btn-download { background: var(--ltv-green); color: #fff; margin-top: 10px; width: 100%; }

.ltv-status { margin-top: 12px; font-size: 13px; min-height: 18px; color: var(--ltv-muted); }
.ltv-status.ltv-err { color: #dc2626; font-weight: 600; }
.ltv-status.ltv-ok { color: var(--ltv-green); font-weight: 600; }

/* 16:9 stage */
.ltv-stage-wrap { width: 100%; }
.ltv-stage {
    width: 100%;
    aspect-ratio: 16 / 9;
    background: #ffffff;
    border: 1px solid var(--ltv-border);
    border-radius: 8px;
    overflow: hidden;
    position: relative;
}
/* The render layer is the true video size (1920 wide); JS scales it to fit. */
.ltv-render {
    position: absolute;
    top: 0; left: 0;
    width: 1920px;
    height: 1080px;
    box-sizing: border-box;
    padding: 165px 165px;
    transform-origin: top left;
    font-weight: 700;
    font-size: 24px;
    line-height: 1.5;
    text-align: left;
    color: #fff;
    word-break: break-word;
    overflow-wrap: break-word;
    display: flex;
    flex-direction: column;
    justify-content: center;
}
.ltv-render .katex { font-weight: 700; }

/* document mode: left-aligned text + math */
.ltv-doc { text-align: left; width: 100%; }
.ltv-doc .ltv-line { margin: 0.15em 0; white-space: normal; word-break: break-word; overflow-wrap: break-word; max-width: 100%; }
.ltv-doc .katex-display { margin: 0.4em 0; }

/* mode toggle */
.ltv-mode-row { display: flex; gap: 16px; flex-wrap: wrap; }
.ltv-radio { font-size: 13px; font-weight: 600; display: flex; align-items: center; gap: 6px; cursor: pointer; }
.ltv-radio input { accent-color: var(--ltv-primary); }

/* narration options */
.ltv-narrate-opts { margin-top: 8px; padding-left: 24px; display: flex; flex-direction: column; gap: 6px; }
.ltv-mini-label { font-size: 12px; font-weight: 600; color: var(--ltv-muted); }
.ltv-select { padding: 6px 8px; border: 1px solid var(--ltv-border); border-radius: 6px; font-size: 13px; background: #fff; max-width: 100%; }
.ltv-narrate-opts input[type="range"] { width: 100%; accent-color: var(--ltv-primary); }

.ltv-video-wrap { margin-top: 16px; }
.ltv-video { width: 100%; border-radius: 8px; background: #000; aspect-ratio: 16/9; }

/* typewriter speed control */
.ltv-speed-note { margin-top: 6px; font-size: 11px; color: var(--ltv-muted); line-height: 1.4; }
#ltv-speed { width: 100%; accent-color: var(--ltv-primary); }

/* image insert + background controls */
.ltv-imgrow { margin: 10px 0; display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.ltv-mini-btn { padding: 6px 12px; font-size: 12px; font-weight: 700; border: 1px solid var(--ltv-primary); color: var(--ltv-primary); background: #fff; border-radius: 6px; cursor: pointer; }
.ltv-mini-btn:hover { background: var(--ltv-primary); color: #fff; }
.ltv-mini-btn-ghost { border-color: var(--ltv-border); color: var(--ltv-muted); }
.ltv-mini-btn-ghost:hover { background: #eef2f7; color: #334155; }
.ltv-imghint { font-size: 11px; color: var(--ltv-muted); flex: 1; min-width: 160px; }
.ltv-bg-opts { margin-top: 8px; display: flex; gap: 8px; flex-wrap: wrap; }
/* rendered images inside the doc */
.ltv-doc img.ltv-embed { display: block; max-width: 80%; max-height: 520px; margin: 14px auto; border-radius: 4px; }

/* start/end slide inputs */
.ltv-textarea-sm { min-height: 80px; }
.ltv-label { display: block; font-weight: 700; font-size: 13px; margin: 14px 0 5px; color: var(--ltv-text, #1a2b4a); }