diff --git a/Cargo.lock b/Cargo.lock
index 4f870fe..9dad18e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4610,15 +4610,6 @@ version = "0.4.29"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5e5032e24019045c762d3c0f28f5b6b8bbf38563a65908389bf7978758920897"
 
-[[package]]
-name = "lol_alloc"
-version = "0.4.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "83e5106554cabc97552dcadf54f57560ae6af3276652f82ca2be06120dc4c5dc"
-dependencies = [
- "spin 0.9.8",
-]
-
 [[package]]
 name = "longest-increasing-subsequence"
 version = "0.1.0"
@@ -8133,7 +8124,6 @@ dependencies = [
  "jacquard-common",
  "jacquard-derive",
  "js-sys",
- "lol_alloc",
  "miette",
  "mime-sniffer",
  "mini-moka-wasm",
diff --git a/Cargo.toml b/Cargo.toml
index 458aaa3..7ab41a0 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -77,7 +77,6 @@ gloo-timers = "0.3"
 gloo-worker = { version = "0.5", features = ["futures"] }
 postcard = { version = "1.1", features = ["use-std"] }
 percent-encoding = "2"
-lol_alloc = "0.4.1"
 mini-moka-wasm = { git = "https://tangled.org/nonbinary.computer/jacquard", branch = "main", features = ["js"] }
 
 [target.'cfg(not(all(target_family = "wasm", target_os = "unknown")))'.dependencies]
@@ -91,9 +90,10 @@ mini-moka-wasm = { git = "https://tangled.org/nonbinary.computer/jacquard", bran
 [dev-dependencies]
 insta = { version = "1.40", features = ["yaml"] }
 
-# Worker WASM build: max speed, aggressive inlining, thin LTO.
+# Worker WASM build: max speed, aggressive inlining, fat LTO.
 # Used by build-workers.sh via `cargo build --profile worker-release`.
 [profile.worker-release]
+panic = "abort"
 inherits = "release"
 opt-level = 3
 lto = "fat"
diff --git a/build-workers.sh b/build-workers.sh
index bd30a03..eab0326 100755
--- a/build-workers.sh
+++ b/build-workers.sh
@@ -21,7 +21,7 @@ if command -v wasm-opt &>/dev/null; then
     echo "==> Running wasm-opt"
     BEFORE=$(stat -c%s public/player_worker_bg.wasm)
     wasm-opt public/player_worker_bg.wasm \
-        -O3 \
+        -O4 \
         --enable-bulk-memory \
         --enable-simd \
         --enable-nontrapping-float-to-int \
diff --git a/crates/ass-renderer/src/pipeline/shaping/mod.rs b/crates/ass-renderer/src/pipeline/shaping/mod.rs
index 2c05b71..ffa5a68 100644
--- a/crates/ass-renderer/src/pipeline/shaping/mod.rs
+++ b/crates/ass-renderer/src/pipeline/shaping/mod.rs
@@ -300,6 +300,7 @@ pub(crate) fn find_font(
 
     // If the requested font contains "CJK" or is a known Japanese font name, try fallbacks
     let is_japanese_font = family.contains("CJK")
+        || family.contains("M PLUS")
         || family.contains("Noto Sans JP")
         || family.contains("Hiragino")
         || family.contains("Yu Gothic")
@@ -309,6 +310,7 @@ pub(crate) fn find_font(
     if is_japanese_font {
         // Try common Japanese font fallbacks
         let japanese_fallbacks = [
+            "M PLUS 2",
             "Hiragino Sans",
             "Hiragino Kaku Gothic Pro",
             "Yu Gothic",
@@ -520,6 +522,7 @@ fn find_font_for_text(
             ],
             // Japanese
             &[
+                "M PLUS 2",
                 "Noto Sans CJK JP",
                 "Noto Sans JP",
                 "Hiragino Sans",
@@ -530,6 +533,8 @@ fn find_font_for_text(
             ],
             // Korean
             &[
+                "NanumGothic",
+                "Nanum Gothic",
                 "Noto Sans CJK KR",
                 "Noto Sans KR",
                 "Apple SD Gothic Neo",
diff --git a/crates/ass-renderer/src/pipeline/software_pipeline.rs b/crates/ass-renderer/src/pipeline/software_pipeline.rs
index 54572aa..2362cf2 100644
--- a/crates/ass-renderer/src/pipeline/software_pipeline.rs
+++ b/crates/ass-renderer/src/pipeline/software_pipeline.rs
@@ -502,7 +502,7 @@ impl SoftwarePipeline {
                 tags.colors.alpha,
                 tags.movement,
                 tags.position,
-                &segment.text[..segment.text.len().min(30)]
+                &segment.text[..segment.text.char_indices().nth(30).map_or(segment.text.len(), |(i, _)| i)]
             );
 
             // Calculate scaling factors
@@ -958,7 +958,7 @@ impl SoftwarePipeline {
                 let italic = tags.formatting.italic.unwrap_or(default_italic);
                 log::trace!(
                     "SEG: text='{}' total_advance={:.1} width={:.1} fscx={:.2} seg_advance={:.1} current_x={:.1}",
-                    &line_text[..line_text.len().min(10)],
+                    &line_text[..line_text.char_indices().nth(10).map_or(line_text.len(), |(i, _)| i)],
                     shaped.total_advance().unwrap_or(-1.0),
                     shaped.width,
                     font_scale_x,
@@ -987,7 +987,7 @@ impl SoftwarePipeline {
 
                     log::trace!(
                         "POS DEBUG: text='{}' anchor=({:.1},{:.1}) total_line_width={:.1} shaped.width={:.1} fscx={:.2} alignment={} playres={}x{} canvas={}x{}",
-                        &line_text[..line_text.len().min(20)],
+                        &line_text[..line_text.char_indices().nth(20).map_or(line_text.len(), |(i, _)| i)],
                         anchor_x, anchor_y,
                         total_line_width, shaped.width, font_scale_x,
                         alignment,
diff --git a/crates/ass-tool/src/main.rs b/crates/ass-tool/src/main.rs
index 8d5792b..7a8b844 100644
--- a/crates/ass-tool/src/main.rs
+++ b/crates/ass-tool/src/main.rs
@@ -113,7 +113,7 @@ enum Command {
     /// Renders subtitle frames at given centisecond timestamps using the
     /// software renderer. Optionally composites onto video frames from an
     /// MKV/MP4 file decoded with ffmpeg. Without --video, composites onto
-    /// a solid black background.
+    /// a solid background (default #333333, configurable via --background).
     Render {
         /// Input ASS file
         ass_file: PathBuf,
@@ -141,6 +141,10 @@ enum Command {
         /// Override render height (default: from ASS PlayResY or 1080)
         #[arg(long)]
         height: Option<u32>,
+
+        /// Background colour when no --video is given (hex, e.g. "#333333")
+        #[arg(long, default_value = "#333333")]
+        background: String,
     },
 
     /// Render ASS subtitles composited onto a video, producing an MP4 output
@@ -344,12 +348,14 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
             output_dir,
             width,
             height,
+            background,
         } => {
+            let bg = parse_hex_colour(&background)?;
             let ts = resolve_timestamps(timestamps, range.as_deref())?;
             if ts.is_empty() {
                 return Err("no timestamps specified: use --timestamps or --range".into());
             }
-            render_frames(&ass_file, &ts, video.as_deref(), &output_dir, width, height)?;
+            render_frames(&ass_file, &ts, video.as_deref(), &output_dir, width, height, bg)?;
         }
 
         Command::RenderVideo {
@@ -1131,6 +1137,17 @@ fn extract_fn_tags_from_text(text: &str, fonts: &mut BTreeSet<String>) {
 // ── Render subcommand ───────────────────────────────────────────────────────
 
 /// Parse --timestamps and --range into a sorted Vec of centisecond timestamps.
+fn parse_hex_colour(s: &str) -> Result<[u8; 3], Box<dyn std::error::Error>> {
+    let hex = s.strip_prefix('#').unwrap_or(s);
+    if hex.len() != 6 || !hex.is_ascii() {
+        return Err(format!("invalid hex colour: {s} (expected #RRGGBB)").into());
+    }
+    let r = u8::from_str_radix(&hex[0..2], 16)?;
+    let g = u8::from_str_radix(&hex[2..4], 16)?;
+    let b = u8::from_str_radix(&hex[4..6], 16)?;
+    Ok([r, g, b])
+}
+
 fn resolve_timestamps(
     timestamps: Option<Vec<u32>>,
     range: Option<&str>,
@@ -1266,6 +1283,7 @@ fn render_frames(
     output_dir: &Path,
     width_override: Option<u32>,
     height_override: Option<u32>,
+    bg_colour: [u8; 3],
 ) -> Result<(), Box<dyn std::error::Error>> {
     let ass_text = fs::read_to_string(ass_path)?;
     let script = ass_core::parser::Script::parse(&ass_text)
@@ -1306,11 +1324,12 @@ fn render_frames(
 
         let subtitle_rgba = frame.pixels();
 
-        // Get background: video frame or solid black
+        // Get background: video frame or solid colour
         let mut canvas = if let Some(ref mut decoder) = video_decoder {
             decoder.decode_frame_at(ts)?.to_vec()
         } else {
-            vec![0u8; (width * height * 4) as usize]
+            let pixel = [bg_colour[0], bg_colour[1], bg_colour[2], 0xFF];
+            pixel.repeat((width * height) as usize)
         };
 
         // Alpha-composite subtitle RGBA onto canvas
diff --git a/crates/vodplace-player-worker/src/subtitle.rs b/crates/vodplace-player-worker/src/subtitle.rs
index f2b95b0..b8ae335 100644
--- a/crates/vodplace-player-worker/src/subtitle.rs
+++ b/crates/vodplace-player-worker/src/subtitle.rs
@@ -17,21 +17,156 @@ use web_sys::{
 
 use crate::font_resolver;
 
-/// Default font URLs — Noto Sans (Latin) and Noto Sans SC Regular + Bold.
+/// Eagerly loaded font URLs — small Latin default, fetched immediately.
 ///
-/// Noto Sans is the default font in converted subtitles (VTT/SRT -> ASS).
-/// Noto Sans SC provides chinese fallback. URLs are from the Google Fonts CSS2 API.
-const DEFAULT_FONT_URLS: &[&str] = &[
-    // Noto Sans — Regular (400)
-    "https://fonts.gstatic.com/s/notosans/v42/o-0mIpQlx3QUlC5A4PNB6Ryti20_6n1iPHjcz6L1SoM-jCpoiyD9A99d.ttf",
-    // Noto Sans — Bold (700)
-    "https://fonts.gstatic.com/s/notosans/v42/o-0mIpQlx3QUlC5A4PNB6Ryti20_6n1iPHjcz6L1SoM-jCpoiyAaBN9d.ttf",
-    // Noto Sans SC — Regular (400)
-    "https://fonts.gstatic.com/s/notosanssc/v40/k3kCo84MPvpLmixcA63oeAL7Iqp5IZJF9bmaG9_FnYw.ttf",
-    // Noto Sans SC — Bold (700)
-    "https://fonts.gstatic.com/s/notosanssc/v40/k3kCo84MPvpLmixcA63oeAL7Iqp5IZJF9bmaGzjCnYw.ttf",
+/// Proza Libre Medium (97KB) is the default font for converted subtitles.
+/// Loaded on first subtitle use so Latin text renders without delay.
+const EAGER_FONT_URLS: &[&str] = &[
+    // Proza Libre — Medium (500), default subtitle font
+    "https://fonts.gstatic.com/s/prozalibre/v9/LYjbdGHgj0k1DIQRyUEyyELbV__f.ttf",
 ];
 
+/// Script-specific font URLs — loaded on demand when subtitle text contains
+/// characters from the corresponding Unicode ranges.
+///
+/// Each entry is (family_name, detect_fn_name, &[urls]). Fonts are fetched
+/// only when needed, keeping initial load to just the ~97KB Latin default.
+///
+/// The `detect` field name corresponds to the script detection function used
+/// in `load_script_fonts_for_content`.
+const SCRIPT_FONT_SETS: &[ScriptFontSet] = &[
+    // ── CJK (large fonts, 2–13MB each) ──────────────────────────────────────
+    ScriptFontSet {
+        family: "M PLUS 2",
+        script: Script::Japanese,
+        urls: &[
+            "https://fonts.gstatic.com/s/mplus2/v15/7Auhp_Eq3gO_OGbGGhjdwrDdpeIBxlkwOa6Vxg.ttf",
+            "https://fonts.gstatic.com/s/mplus2/v15/7Auhp_Eq3gO_OGbGGhjdwrDdpeIBxlkw3qmVxg.ttf",
+        ],
+    },
+    ScriptFontSet {
+        family: "Noto Sans SC",
+        script: Script::ChineseSc,
+        urls: &[
+            "https://fonts.gstatic.com/s/notosanssc/v40/k3kCo84MPvpLmixcA63oeAL7Iqp5IZJF9bmaG9_FnYw.ttf",
+            "https://fonts.gstatic.com/s/notosanssc/v40/k3kCo84MPvpLmixcA63oeAL7Iqp5IZJF9bmaGzjCnYw.ttf",
+        ],
+    },
+    ScriptFontSet {
+        family: "Noto Sans TC",
+        script: Script::ChineseTc,
+        urls: &[
+            "https://fonts.gstatic.com/s/notosanstc/v39/-nFuOG829Oofr2wohFbTp9ifNAn722rq0MXz76Cy_Co.ttf",
+            "https://fonts.gstatic.com/s/notosanstc/v39/-nFuOG829Oofr2wohFbTp9ifNAn722rq0MXz70e1_Co.ttf",
+        ],
+    },
+    ScriptFontSet {
+        family: "NanumGothic",
+        script: Script::Korean,
+        urls: &[
+            "https://fonts.gstatic.com/s/nanumgothic/v26/PN_3Rfi-oW3hYwmKDpxS7F_D-djb.ttf",
+            "https://fonts.gstatic.com/s/nanumgothic/v26/PN_oRfi-oW3hYwmKDpxS7F_LQv3LyVsj.ttf",
+        ],
+    },
+    // ── Cyrillic + Greek (Inter covers both, ~300KB) ─────────────────────────
+    ScriptFontSet {
+        family: "Inter",
+        script: Script::CyrillicOrGreek,
+        urls: &[
+            "https://fonts.gstatic.com/s/inter/v20/UcCO3FwrK3iLTeHuS_nVMrMxCp50SjIw2boKoduKmMEVuLyfMZg.ttf",
+        ],
+    },
+    // ── Arabic (~200KB) ──────────────────────────────────────────────────────
+    ScriptFontSet {
+        family: "Tajawal",
+        script: Script::Arabic,
+        urls: &[
+            "https://fonts.gstatic.com/s/tajawal/v12/Iura6YBj_oCad4k1rzY.ttf",
+        ],
+    },
+    // ── Devanagari (~150KB) ──────────────────────────────────────────────────
+    ScriptFontSet {
+        family: "Poppins",
+        script: Script::Devanagari,
+        urls: &[
+            "https://fonts.gstatic.com/s/poppins/v24/pxiEyp8kv8JHgFVrFJA.ttf",
+        ],
+    },
+    // ── Thai (~100KB) ────────────────────────────────────────────────────────
+    ScriptFontSet {
+        family: "Sarabun",
+        script: Script::Thai,
+        urls: &[
+            "https://fonts.gstatic.com/s/sarabun/v17/DtVjJx26TKEr37c9WBI.ttf",
+        ],
+    },
+    // ── Hebrew (~100KB) ──────────────────────────────────────────────────────
+    ScriptFontSet {
+        family: "Heebo",
+        script: Script::Hebrew,
+        urls: &[
+            "https://fonts.gstatic.com/s/heebo/v28/NGSpv5_NC0k9P_v6ZUCbLRAHxK1EiSyccg.ttf",
+        ],
+    },
+    // ── Bengali (~200KB) ─────────────────────────────────────────────────────
+    ScriptFontSet {
+        family: "Hind Siliguri",
+        script: Script::Bengali,
+        urls: &[
+            "https://fonts.gstatic.com/s/hindsiliguri/v14/ijwTs5juQtsyLLR5jN4cxBEofJs.ttf",
+        ],
+    },
+    // ── Tamil (~200KB) ───────────────────────────────────────────────────────
+    ScriptFontSet {
+        family: "Catamaran",
+        script: Script::Tamil,
+        urls: &[
+            "https://fonts.gstatic.com/s/catamaran/v28/o-0bIpQoyXQa2RxT7-5B6Ryxs2E_6n1iPHjd1ak.ttf",
+        ],
+    },
+    // ── Telugu (~200KB) ──────────────────────────────────────────────────────
+    ScriptFontSet {
+        family: "Hind Guntur",
+        script: Script::Telugu,
+        urls: &[
+            "https://fonts.gstatic.com/s/hindguntur/v14/wXKvE3UZrok56nvamSuJd8Qq.ttf",
+        ],
+    },
+    // ── Universal fallback: Noto Sans base (Latin/Greek/Cyrillic, ~570KB) ────
+    // Loaded as last resort when no preferred font covers the text.
+    ScriptFontSet {
+        family: "Noto Sans",
+        script: Script::UniversalFallback,
+        urls: &[
+            "https://fonts.gstatic.com/s/notosans/v42/o-0mIpQlx3QUlC5A4PNB6Ryti20_6n1iPHjcz6L1SoM-jCpoiyD9A99d.ttf",
+            "https://fonts.gstatic.com/s/notosans/v42/o-0mIpQlx3QUlC5A4PNB6Ryti20_6n1iPHjcz6L1SoM-jCpoiyAaBN9d.ttf",
+        ],
+    },
+];
+
+struct ScriptFontSet {
+    family: &'static str,
+    script: Script,
+    urls: &'static [&'static str],
+}
+
+#[derive(Clone, Copy, PartialEq)]
+enum Script {
+    Japanese,
+    ChineseSc,
+    ChineseTc,
+    Korean,
+    CyrillicOrGreek,
+    Arabic,
+    Devanagari,
+    Thai,
+    Hebrew,
+    Bengali,
+    Tamil,
+    Telugu,
+    UniversalFallback,
+}
+
 // ── Error type ────────────────────────────────────────────────────────────────
 
 /// Errors that can occur during subtitle state operations.
@@ -231,25 +366,20 @@ impl SubtitleState {
         }
     }
 
-    /// Fetch and load the default font (Noto Sans SC) from the Google Fonts CDN.
-    ///
-    /// Sets `self.fonts_loaded = true` after the attempt (whether it succeeded
-    /// or failed) so that subsequent `load_script` calls do not retry.
+    /// Fetch and load the default Latin font (Proza Libre) from Google Fonts.
     ///
-    /// On success, rebuilds the renderer context so the new font is available
-    /// for shaping on the next `render_at` call.
+    /// Only loads the small (~97KB) Latin default eagerly. CJK fonts are loaded
+    /// on demand by [`resolve_script_fonts`] based on the actual script content.
     ///
-    /// On failure, logs a warning and continues — the pipeline will still
-    /// render (possibly with missing-glyph boxes).
+    /// Sets `self.fonts_loaded = true` after the attempt (whether it succeeded
+    /// or failed) so that subsequent calls do not retry.
     pub async fn load_default_font(&mut self) {
-        // Mark as attempted immediately so that a failure does not cause
-        // every subsequent load_script call to retry the fetch.
         self.fonts_loaded = true;
 
         let mut total_bytes = 0usize;
         let mut loaded = 0usize;
-        for url in DEFAULT_FONT_URLS {
-            web_sys::console::log_1(&format!("subtitle: fetching font from {url}").into());
+        for url in EAGER_FONT_URLS {
+            web_sys::console::log_1(&format!("subtitle: fetching default font from {url}").into());
             match fetch_font_bytes(url).await {
                 Ok(font_bytes) => {
                     total_bytes += font_bytes.len();
@@ -264,20 +394,111 @@ impl SubtitleState {
             }
         }
         // Register generic family aliases so fontdb's Family::SansSerif
-        // queries resolve to a loaded font. Without this, the fallback
-        // chain in find_font() can't find a generic sans-serif.
-        self.font_db.set_sans_serif_family("Noto Sans");
-        self.font_db.set_serif_family("Noto Sans");
+        // queries resolve to a loaded font.
+        self.font_db.set_sans_serif_family("Proza Libre");
+        self.font_db.set_serif_family("Proza Libre");
 
-        // Track loaded families so resolve_script_fonts can skip them.
-        font_resolver::register_font_name("Noto Sans", &mut self.loaded_families);
-        font_resolver::register_font_name("Noto Sans SC", &mut self.loaded_families);
+        font_resolver::register_font_name("Proza Libre", &mut self.loaded_families);
 
         self.publish_font_db();
 
         log::info!(
-            "subtitle: {loaded}/{} default fonts loaded ({total_bytes} bytes)",
-            DEFAULT_FONT_URLS.len()
+            "subtitle: {loaded}/{} eager fonts loaded ({total_bytes} bytes)",
+            EAGER_FONT_URLS.len()
+        );
+    }
+
+    /// Load script-specific font sets needed for the current subtitle content.
+    ///
+    /// Scans all dialogue text to detect which Unicode script ranges are present,
+    /// then fetches only the font sets actually needed. This avoids eagerly
+    /// downloading large CJK fonts (~10MB+) or other script fonts when the
+    /// content is Latin-only.
+    async fn load_script_fonts_for_content(&mut self) {
+        let text = match self.script.as_ref() {
+            Some(owned) => owned.with_script(|script| {
+                use ass_core::parser::Section;
+                let mut buf = String::new();
+                for section in script.sections() {
+                    if let Section::Events(events) = section {
+                        for event in events {
+                            buf.push_str(event.text);
+                            buf.push(' ');
+                        }
+                    }
+                }
+                buf
+            }),
+            None => return,
+        };
+
+        if text.is_empty() {
+            return;
+        }
+
+        // Detect which scripts are present in the subtitle text.
+        // Each flag is set lazily — we only scan until we find a match.
+        let mut detected = [false; 13];
+        for c in text.chars() {
+            if is_japanese_char(c) { detected[Script::Japanese as usize] = true; }
+            if is_cjk_unified(c) {
+                detected[Script::ChineseSc as usize] = true;
+                detected[Script::ChineseTc as usize] = true;
+            }
+            if is_hangul_char(c) { detected[Script::Korean as usize] = true; }
+            if is_cyrillic_char(c) || is_greek_char(c) { detected[Script::CyrillicOrGreek as usize] = true; }
+            if is_arabic_char(c) { detected[Script::Arabic as usize] = true; }
+            if is_devanagari_char(c) { detected[Script::Devanagari as usize] = true; }
+            if is_thai_char(c) { detected[Script::Thai as usize] = true; }
+            if is_hebrew_char(c) { detected[Script::Hebrew as usize] = true; }
+            if is_bengali_char(c) { detected[Script::Bengali as usize] = true; }
+            if is_tamil_char(c) { detected[Script::Tamil as usize] = true; }
+            if is_telugu_char(c) { detected[Script::Telugu as usize] = true; }
+        }
+
+        let mut sets_to_load: Vec<&ScriptFontSet> = Vec::new();
+        for set in SCRIPT_FONT_SETS {
+            if set.script == Script::UniversalFallback {
+                continue; // loaded separately as last resort
+            }
+            if detected[set.script as usize]
+                && !font_resolver::is_family_loaded(set.family, &self.loaded_families)
+            {
+                sets_to_load.push(set);
+            }
+        }
+
+        if sets_to_load.is_empty() {
+            return;
+        }
+
+        log::info!(
+            "subtitle: loading {} script font set(s): {:?}",
+            sets_to_load.len(),
+            sets_to_load.iter().map(|s| s.family).collect::<Vec<_>>()
+        );
+
+        let mut total_bytes = 0usize;
+        for set in &sets_to_load {
+            for url in set.urls {
+                match fetch_font_bytes(url).await {
+                    Ok(font_bytes) => {
+                        total_bytes += font_bytes.len();
+                        self.font_db.load_font_data(font_bytes);
+                    }
+                    Err(e) => {
+                        log::warn!("subtitle: failed to load font {url}: {e}");
+                    }
+                }
+            }
+            font_resolver::register_font_name(set.family, &mut self.loaded_families);
+        }
+
+        self.publish_font_db();
+
+        log::info!(
+            "subtitle: loaded {} script font set(s) ({total_bytes} bytes)",
+            sets_to_load.len()
         );
     }
 
@@ -290,6 +511,9 @@ impl SubtitleState {
     /// Call after `load_script` and `ensure_fonts_loaded` so that default
     /// fonts are already in the database.
     pub async fn resolve_script_fonts(&mut self) {
+        // 0. Load script-specific font sets based on actual subtitle content
+        self.load_script_fonts_for_content().await;
+
         // 1. Load embedded fonts from the [Fonts] section
         self.load_embedded_fonts();
 
@@ -1451,3 +1675,65 @@ pub async fn fetch_and_load_hls_subtitles(
 
     Ok(())
 }
+
+// ── Script detection helpers ─────────────────────────────────────────────────
+
+/// Japanese kana + CJK ideographs (Hiragana, Katakana, common kanji).
+fn is_japanese_char(c: char) -> bool {
+    matches!(c, '\u{3040}'..='\u{309F}' | '\u{30A0}'..='\u{30FF}' | '\u{4E00}'..='\u{9FFF}')
+}
+
+/// CJK Unified Ideographs (shared across Chinese/Japanese/Korean).
+fn is_cjk_unified(c: char) -> bool {
+    matches!(c, '\u{4E00}'..='\u{9FFF}' | '\u{3400}'..='\u{4DBF}' | '\u{20000}'..='\u{2A6DF}')
+}
+
+/// Hangul syllables and Jamo.
+fn is_hangul_char(c: char) -> bool {
+    matches!(c, '\u{AC00}'..='\u{D7AF}' | '\u{1100}'..='\u{11FF}' | '\u{3130}'..='\u{318F}')
+}
+
+/// Cyrillic (U+0400–04FF) + extended blocks.
+fn is_cyrillic_char(c: char) -> bool {
+    matches!(c, '\u{0400}'..='\u{04FF}' | '\u{0500}'..='\u{052F}' | '\u{2DE0}'..='\u{2DFF}' | '\u{A640}'..='\u{A69F}')
+}
+
+/// Greek and Coptic (U+0370–03FF) + extended.
+fn is_greek_char(c: char) -> bool {
+    matches!(c, '\u{0370}'..='\u{03FF}' | '\u{1F00}'..='\u{1FFF}')
+}
+
+/// Arabic (U+0600–06FF) + supplement + extended blocks.
+fn is_arabic_char(c: char) -> bool {
+    matches!(c, '\u{0600}'..='\u{06FF}' | '\u{0750}'..='\u{077F}' | '\u{08A0}'..='\u{08FF}' | '\u{FB50}'..='\u{FDFF}' | '\u{FE70}'..='\u{FEFF}')
+}
+
+/// Devanagari (U+0900–097F) + extended.
+fn is_devanagari_char(c: char) -> bool {
+    matches!(c, '\u{0900}'..='\u{097F}' | '\u{A8E0}'..='\u{A8FF}')
+}
+
+/// Thai (U+0E00–0E7F).
+fn is_thai_char(c: char) -> bool {
+    matches!(c, '\u{0E00}'..='\u{0E7F}')
+}
+
+/// Hebrew (U+0590–05FF) + presentation forms.
+fn is_hebrew_char(c: char) -> bool {
+    matches!(c, '\u{0590}'..='\u{05FF}' | '\u{FB1D}'..='\u{FB4F}')
+}
+
+/// Bengali (U+0980–09FF).
+fn is_bengali_char(c: char) -> bool {
+    matches!(c, '\u{0980}'..='\u{09FF}')
+}
+
+/// Tamil (U+0B80–0BFF).
+fn is_tamil_char(c: char) -> bool {
+    matches!(c, '\u{0B80}'..='\u{0BFF}')
+}
+
+/// Telugu (U+0C00–0C7F).
+fn is_telugu_char(c: char) -> bool {
+    matches!(c, '\u{0C00}'..='\u{0C7F}')
+}
diff --git a/crates/vodplace-subtitle/src/ass_gen.rs b/crates/vodplace-subtitle/src/ass_gen.rs
index ca4e881..6f5439b 100644
--- a/crates/vodplace-subtitle/src/ass_gen.rs
+++ b/crates/vodplace-subtitle/src/ass_gen.rs
@@ -17,17 +17,30 @@ PlayResY: {height}
     )
 }
 
-/// Generate the `[V4+ Styles]` section with a sensible default style.
+/// Generate the `[V4+ Styles]` section with the standard subtitle style.
 ///
-/// Uses Noto Sans, white text, size 46, bottom-centre alignment (\\an2),
-/// with outline and semi-transparent shadow. Font size 46 at PlayRes
-/// 1920x1080 matches the BBC HD broadcast standard (~4.3% of height)
-/// and scales proportionally to the actual render resolution.
+/// Uses Proza Libre, white text, size 72, bottom-centre alignment (\\an2),
+/// with outline (3.6) and semi-transparent shadow (1.5). Style parameters
+/// match the conventions of professional fansub groups at 1920×1080
+/// PlayRes and scale proportionally to the actual render resolution.
 pub fn default_style() -> &'static str {
     "\
 [V4+ Styles]
 Format: Name, Fontname, Fontsize, PrimaryColour, SecondaryColour, OutlineColour, BackColour, Bold, Italic, Underline, StrikeOut, ScaleX, ScaleY, Spacing, Angle, BorderStyle, Outline, Shadow, Alignment, MarginL, MarginR, MarginV, Encoding
-Style: Default,Noto Sans,46,&H00FFFFFF,&H000000FF,&H00000000,&H80000000,0,0,0,0,100,100,0,0,1,4,1,2,10,10,120,1
+Style: Default,Proza Libre,72,&H00FFFFFF,&H00FFFFFF,&H00000000,&HA0000000,0,0,0,0,100,100,0,0,1,3.6,1.5,2,180,180,60,1
+"
+}
+
+/// Generate the `[V4+ Styles]` section for ionosphere transcripts.
+///
+/// Same font and styling as [`default_style`] but with a higher bottom
+/// margin (MarginV 120) to push subtitles above the conference VOD
+/// speaker bar area.
+pub fn ionosphere_style() -> &'static str {
+    "\
+[V4+ Styles]
+Format: Name, Fontname, Fontsize, PrimaryColour, SecondaryColour, OutlineColour, BackColour, Bold, Italic, Underline, StrikeOut, ScaleX, ScaleY, Spacing, Angle, BorderStyle, Outline, Shadow, Alignment, MarginL, MarginR, MarginV, Encoding
+Style: Default,Proza Libre,72,&H00FFFFFF,&H00FFFFFF,&H00000000,&HA0000000,0,0,0,0,100,100,0,0,1,3.6,1.5,2,180,180,120,1
 "
 }
 
@@ -170,7 +183,28 @@ mod tests {
         let style = default_style();
         assert!(style.contains("[V4+ Styles]"));
         assert!(style.contains("Style: Default,"));
-        assert!(style.contains("Noto Sans"));
+        assert!(style.contains("Proza Libre"));
+    }
+
+    #[test]
+    fn ionosphere_style_is_valid() {
+        let style = ionosphere_style();
+        assert!(style.contains("[V4+ Styles]"));
+        assert!(style.contains("Style: Default,"));
+        assert!(style.contains("Proza Libre"));
+        assert!(style.contains(",120,1"), "ionosphere style should have MarginV 120");
+    }
+
+    #[test]
+    fn ionosphere_style_differs_from_default_only_in_margin() {
+        let default = default_style();
+        let iono = ionosphere_style();
+        // Both use the same font
+        assert!(default.contains("Proza Libre"));
+        assert!(iono.contains("Proza Libre"));
+        // Different bottom margins
+        assert!(default.contains(",60,1"), "default should have MarginV 60");
+        assert!(iono.contains(",120,1"), "ionosphere should have MarginV 120");
     }
 
     #[test]
diff --git a/crates/vodplace-subtitle/src/convert_ionosphere.rs b/crates/vodplace-subtitle/src/convert_ionosphere.rs
index 9f297a5..3a5fc29 100644
--- a/crates/vodplace-subtitle/src/convert_ionosphere.rs
+++ b/crates/vodplace-subtitle/src/convert_ionosphere.rs
@@ -66,7 +66,7 @@ pub fn ionosphere_to_ass(
         "Converted from ionosphere transcript",
     ));
     ass.push('\n');
-    ass.push_str(&ass_gen::default_style());
+    ass.push_str(&ass_gen::ionosphere_style());
     ass.push('\n');
     ass.push_str(&ass_gen::events_header());