Firefox uses "hardware acceleration" to smooth fonts, so if Firefox has become incompatible with your graphics card (or graphics chipset) driver software, that might explain why fonts could look jaggy.

There is a section of the Troubleshooting Information page that summarizes your graphics configuration and how Firefox is working with it. Could you copy/paste that section of the page into a reply? Either:

• "3-bar" menu button > "?" Help > Troubleshooting Information
• (menu bar) Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter

The Graphics section is about 1/3 of the way down the page and goes on for quite a ways. If you select that with the mouse, you should be able to copy it using Ctrl+c or right-click > Copy, then you can paste into a reply.

The issue is with the set-up of the toolbars up top. Below is what you requested. Attached is also a screenshot of what the toolbar looks like currently.

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(adapter LUID: 000000000000776e) EGL_VERSION: 1.4 (ANGLE 2.1.0.fcbca0e873c3) EGL_EXTENSIONS: EGL_EXT_create_context_robustness EGL_ANGLE_d3d_share_handle_client_buffer EGL_ANGLE_d3d_texture_client_buffer EGL_ANGLE_surface_d3d_texture_2d_share_handle EGL_ANGLE_query_surface_pointer EGL_ANGLE_window_fixed_size EGL_ANGLE_keyed_mutex EGL_ANGLE_surface_orientation EGL_ANGLE_direct_composition EGL_NV_post_sub_buffer EGL_KHR_create_context EGL_EXT_device_query EGL_KHR_image EGL_KHR_image_base EGL_KHR_gl_texture_2D_image EGL_KHR_gl_texture_cubemap_image EGL_KHR_gl_renderbuffer_image EGL_KHR_get_all_proc_addresses EGL_KHR_stream EGL_KHR_stream_consumer_gltexture EGL_NV_stream_consumer_gltexture_yuv EGL_ANGLE_flexible_surface_compatibility EGL_ANGLE_stream_producer_d3d_texture EGL_ANGLE_create_context_webgl_compatibility EGL_CHROMIUM_create_context_bind_generates_resource EGL_CHROMIUM_sync_control EGL_EXT_pixel_format_float EGL_KHR_surfaceless_context EGL_ANGLE_display_texture_share_group EGL_ANGLE_create_context_client_arrays EGL_ANGLE_program_cache_control EGL_ANGLE_robust_resource_initialization EGL_EXTENSIONS(nullptr): EGL_EXT_client_extensions EGL_EXT_platform_base EGL_EXT_platform_device EGL_ANGLE_platform_angle EGL_ANGLE_platform_angle_d3d EGL_ANGLE_device_creation EGL_ANGLE_device_creation_d3d11 EGL_ANGLE_experimental_present_path EGL_KHR_client_get_all_proc_addresses WebGL 2 Driver Renderer Google Inc. -- ANGLE (Intel(R) HD Graphics 5500 Direct3D11 vs_5_0 ps_5_0) WebGL 2 Driver Version OpenGL ES 3.0 (ANGLE 2.1.0.fcbca0e873c3) WebGL 2 Driver Extensions GL_ANGLE_client_arrays GL_ANGLE_depth_texture GL_ANGLE_framebuffer_blit GL_ANGLE_framebuffer_multisample GL_ANGLE_instanced_arrays GL_ANGLE_lossy_etc_decode GL_ANGLE_multiview GL_ANGLE_pack_reverse_row_order GL_ANGLE_program_cache_control GL_ANGLE_request_extension GL_ANGLE_robust_client_memory GL_ANGLE_texture_compression_dxt3 GL_ANGLE_texture_compression_dxt5 GL_ANGLE_texture_usage GL_ANGLE_translated_shader_source GL_CHROMIUM_bind_generates_resource GL_CHROMIUM_bind_uniform_location GL_CHROMIUM_color_buffer_float_rgb GL_CHROMIUM_color_buffer_float_rgba GL_CHROMIUM_copy_compressed_texture GL_CHROMIUM_copy_texture GL_CHROMIUM_sync_query GL_EXT_blend_minmax GL_EXT_color_buffer_float GL_EXT_color_buffer_half_float GL_EXT_debug_marker GL_EXT_discard_framebuffer GL_EXT_disjoint_timer_query GL_EXT_draw_buffers GL_EXT_frag_depth GL_EXT_map_buffer_range GL_EXT_occlusion_query_boolean GL_EXT_read_format_bgra GL_EXT_robustness GL_EXT_sRGB GL_EXT_shader_texture_lod GL_EXT_texture_compression_dxt1 GL_EXT_texture_compression_s3tc_srgb GL_EXT_texture_filter_anisotropic GL_EXT_texture_format_BGRA8888 GL_EXT_texture_norm16 GL_EXT_texture_rg GL_EXT_texture_storage GL_EXT_unpack_subimage GL_KHR_debug GL_NV_EGL_stream_consumer_external GL_NV_fence GL_NV_pack_subimage GL_NV_pixel_buffer_object GL_OES_EGL_image GL_OES_EGL_image_external GL_OES_EGL_image_external_essl3 GL_OES_compressed_ETC1_RGB8_texture GL_OES_depth32 GL_OES_element_index_uint GL_OES_get_program_binary GL_OES_mapbuffer GL_OES_packed_depth_stencil GL_OES_rgb8_rgba8 GL_OES_standard_derivatives GL_OES_surfaceless_context GL_OES_texture_float GL_OES_texture_float_linear GL_OES_texture_half_float GL_OES_texture_half_float_linear GL_OES_texture_npot GL_OES_vertex_array_object WebGL 2 Extensions EXT_color_buffer_float EXT_texture_filter_anisotropic EXT_disjoint_timer_query OES_texture_float_linear WEBGL_compressed_texture_s3tc WEBGL_compressed_texture_s3tc_srgb WEBGL_debug_renderer_info WEBGL_debug_shaders WEBGL_lose_context Direct2D true Off Main Thread Painting Enabled true Off Main Thread Painting Worker Count 1 DirectWrite true (10.0.14393.1358) GPU #1 Active Yes Description Intel(R) HD Graphics 5500 Vendor ID 0x8086 Device ID 0x1616 Driver Version 20.19.15.4835 Driver Date 10-16-2017 Drivers igdumdim64 igd10iumd64 igd10iumd64 igd12umd64 igdumdim32 igd10iumd32 igd10iumd32 igd12umd32 Subsys ID 062d1028 RAM Unknown Diagnostics AzureCanvasAccelerated 0 AzureCanvasBackend direct2d 1.1 AzureCanvasBackend (UI Process) skia AzureContentBackend direct2d 1.1 AzureContentBackend (UI Process) skia AzureFallbackCanvasBackend (UI Process) cairo GPUProcessPid 7912 Decision Log WEBRENDER opt-in by default: WebRender is an opt-in feature unavailable by runtime: Build doesn't include WebRender

Hi AddaBaranowski, the toolbar font doesn't look that odd to me. Firefox will generally follow your OS settings for title bar and menu fonts. I don't use Windows 10 very often, so I don't remember what is normal. How would you say it is different from what it looked like before?

It sounds trivial, I know, but this is not what i looked like yesterday morning. I may have hit a button on the keyboard. Do you know of any that would trigger a change like that?

Hi AddaBaranowski, I'm pretty sure you can't change the toolbar font with an errant keystroke within Firefox.

The title bar on the top row is optional, but presumably you turned that on intentionally on the Customize screen, using the checkbox in the lower left corner. (Customize Firefox controls, buttons and toolbars)

The menu bar, similarly, is optional. If you were to press the keys

Alt V T M

in sequence, that would turn it on or off, but what are the odds?!

Did the appearance of any other apps change?