diff --git a/.gitignore b/.gitignore
index f7fb5a8..922fed5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,6 @@
 docs/local/
 
 build/
+build-wasm/
+compile_commands.json
+/.emscripten-cache
diff --git a/docs/dd.md b/docs/dd.md
index 9715b77..73f0929 100644
--- a/docs/dd.md
+++ b/docs/dd.md
@@ -72,9 +72,20 @@ color emoji are out of scope for the first versions.
 
 ## Rendering
 
-Rectangles, borders, and glyphs all reduce to quads. A backend only needs to
-manage textures, draw quad batches, and apply a scissor rect. Rendering
-backends are replaceable, and the SDL3 and OpenGL backend is the default.
+The core never calls a backend. Each frame `rg_render` returns a draw list
+made of texture operations (create, update region, destroy) followed by
+batches of colored and textured quads with scissor rects. A backend is any
+code that consumes that list. The SDL3 and OpenGL backend is the default, and
+the null backend records the list for headless tests. A WASM host can consume
+the list from JavaScript. The shipped backends share a small convenience
+interface, and the core does not depend on it.
+
+## Viewport and scale
+
+All API coordinates are logical pixels. The host calls
+`rg_set_viewport(ctx, w, h, scale)` when the window resizes or the display
+scale changes. A scale change invalidates the glyph atlas and glyphs are
+rasterized again at the new size.
 
 ## Documents
 
@@ -144,27 +155,6 @@ across the FFI boundary.
   never by raw pointers.
 - The user can supply an allocator, and internal allocation uses arenas.
 
-## Build and environment
-
-The build system is CMake with Ninja. Development happens on NixOS using
-direnv and flakes, and the devShell provides CMake, Ninja, pkg-config, clang,
-clang-tools, SDL3, Emscripten, and lua-language-server. Emscripten's cache
-directory is set to `.emscripten-cache` inside the project. WASM builds go
-through `emcmake` into `build-wasm/`. Sources live in a flat `src/` with no
-generated files, so Zig and Odin users can compile them with their own
-toolchain.
-
-## Milestone 1
-
-A `main.lua` builds a `VBox` of `Label` and `Button` nodes. A stylesheet with
-classes and a `:hover` state styles them. Layout runs through Clay and draws
-through the SDL3 and OpenGL backend with stb_truetype text. A button click
-fires both a Lua handler and a named event in the polled queue. One
-transition eases a button background on hover. A data-bound label shows a
-counter that the button increments.
-
-Text inputs and scrolling follow in milestone 2, along with focus handling.
-
 ## Context and ownership
 
 All state lives in an `rg_context`, which is created with `rg_create` and
@@ -194,8 +184,47 @@ Gamepad navigation will be added as a semantic layer (up, down, left, right,
 accept, cancel) that drives focus movement, so a game can map any device to
 it.
 
-## Open questions
+## Errors and logging
 
-- Whether texture uploads travel inside the draw list.
-- Viewport and display scale handling.
-- Error reporting and logging.
+Functions that can fail return an `int` status where zero is success and
+negative values are errors. `rg_last_error(ctx)` returns the message for the
+most recent failure on that context. The config carries a log callback, a log
+level, and a userdata pointer. The default callback writes to stderr and the
+default level is trace, so logging is verbose until I lower it. Lua errors
+such as syntax errors and handler failures are logged and never replace the
+live tree, so a broken save during hot reload leaves the last good tree on
+screen.
+
+## Testing
+
+`ctest` runs the smoke tests. The core smoke test installs a counting
+allocator and fails if any bytes are live after `rg_destroy`. Every
+allocation, including Lua's, goes through the context allocator.
+
+### Build and environment
+
+The build system is CMake with Ninja. Development happens on NixOS using
+direnv and flakes, and the devShell provides CMake, Ninja, pkg-config, clang,
+clang-tools, SDL3, Emscripten, and lua-language-server. Emscripten's cache
+directory is set to `.emscripten-cache` inside the project. WASM builds go
+through `emcmake` into `build-wasm/`. Sources live in a flat `src/` with no
+generated files, so Zig and Odin users can compile them with their own
+toolchain.
+
+### Milestone 1
+
+A `main.lua` builds a `VBox` of `Label` and `Button` nodes. A stylesheet with
+classes and a `:hover` state styles them. Layout runs through Clay and draws
+through the SDL3 and OpenGL backend with stb_truetype text. A button click
+fires both a Lua handler and a named event in the polled queue. One
+transition eases a button background on hover. A data-bound label shows a
+counter that the button increments.
+
+Text inputs and scrolling follow in milestone 2, along with focus handling.
+
+
+
+### Open questions
+
+- Node handle format.
+- Property system: how properties are named, typed, and stored.
diff --git a/include/regolith.h b/include/regolith.h
index 59b0952..643b916 100644
--- a/include/regolith.h
+++ b/include/regolith.h
@@ -6,24 +6,22 @@
   Last edit date: 11-02-2026
 */
 
-
-
 #ifndef REGOLITH_H
 #define REGOLITH_H
 
-#include <cstddef>
-#include <cstdint>
+#include <stddef.h>
+#include <stdint.h>
 
 #if defined(_WIN32) && defined(RG_SHARED)
-  #ifdef RG_BUILD
-    #define RG_API __declspec(dllexport)
-  #else
-    #define RG_API __declspec(dllimport)
-  #endif
-#elif defined(__GNUC__)
-  #define RG_API __attribute__((visibility("default")))
+#ifdef RG_BUILD
+#define RG_API __declspec(dllexport)
 #else
-  #define RG_API
+#define RG_API __declspec(dllimport)
+#endif
+#elif defined(__GNUC__)
+#define RG_API __attribute__((visibility("default")))
+#else
+#define RG_API
 #endif
 
 #ifdef __cplusplus
@@ -32,26 +30,27 @@ extern "C" {
 
 #define RG_VERSION_STRING "0.0.1"
 
-
 /*
   TODO: Add documentation comments
 */
- 
+
 enum {
-  RG_LOG_TRACE = 0,
-  RG_LOG_DEBUG,
-  RG_LOG_INFO,
-  RG_LOG_WARN,
-  RG_LOG_ERROR
+  RG_OK = 0,
+  RG_ERR_GENERIC = -1,
+  RG_ERR_NO_MEMORY = -2,
+  RG_ERR_STATE = -3,
+  RG_ERR_LUA = -4
 };
 
+enum { RG_LOG_TRACE = 0, RG_LOG_DEBUG, RG_LOG_INFO, RG_LOG_WARN, RG_LOG_ERROR };
+
 typedef struct rg_context rg_context;
 
 typedef struct rg_allocator {
-  void* (*alloc)(size_t size, void* user);
-  void* (*realloc)(void* ptr, size_t old_size, size_t new_size, void* user);
-  void* (*free)(void* ptr, size_t size, void* user);
-  void* user;
+  void *(*alloc)(size_t size, void *user);
+  void *(*realloc)(void *ptr, size_t old_size, size_t new_size, void *user);
+  void (*free)(void *ptr, size_t size, void *user);
+  void *user;
 } rg_allocator;
 
 typedef void (*rg_log_fn)(int32_t level, const char *message, void *user);
@@ -60,20 +59,18 @@ typedef struct rg_config {
   uint32_t struct_size;
   rg_allocator allocator;
   rg_log_fn log;
-  void* log_user;
+  void *log_user;
   int32_t log_level;
   int32_t viewport_w;
   int32_t viewport_h;
   float display_scale;
 } rg_config;
 
-
-RG_API const char* rg_version(void);
-RG_API void rg_config_init(rg_config* config);
-RG_API rg_context* rg_create(const rg_config* config);
-RG_API void rg_destroy(rg_context* ctx);
-RG_API const char* rg_last_error(const rg_context* ctx);
-
+RG_API const char *rg_version(void);
+RG_API void rg_config_init(rg_config *config);
+RG_API rg_context *rg_create(const rg_config *config);
+RG_API void rg_destroy(rg_context *ctx);
+RG_API const char *rg_last_error(const rg_context *ctx);
 
 #ifdef __cplusplus
 }
diff --git a/src/context.c b/src/context.c
new file mode 100644
index 0000000..20939cb
--- /dev/null
+++ b/src/context.c
@@ -0,0 +1,122 @@
+#include "internal.h"
+
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static void *default_alloc(size_t size, void *user) {
+  (void)user;
+  return malloc(size);
+}
+
+static void *default_realloc(void *ptr, size_t old_size, size_t new_size,
+                             void *user) {
+  (void)old_size;
+  (void)user;
+  return realloc(ptr, new_size);
+}
+
+static void default_free(void *ptr, size_t size, void *user) {
+  (void)size;
+  (void)user;
+  free(ptr);
+}
+
+static void default_log(int32_t level, const char *message, void *user) {
+  static const char *names[] = {"TRACE", "DEBUG", "INFO", "WARN", "ERROR"};
+  (void)user;
+  fprintf(stderr, "[regolith %s] %s\n", names[level], message);
+}
+
+const char *rg_version(void) { return RG_VERSION_STRING; }
+
+void rg_config_init(rg_config *config) {
+  memset(config, 0, sizeof *config);
+  config->struct_size = (uint32_t)sizeof *config;
+  config->allocator.alloc = default_alloc;
+  config->allocator.realloc = default_realloc;
+  config->allocator.free = default_free;
+  config->log = default_log;
+  config->log_level = RG_LOG_TRACE;
+  config->viewport_w = 1280;
+  config->viewport_h = 720;
+  config->display_scale = 1.0f;
+}
+
+void rg__log(rg_context *ctx, int32_t level, const char *fmt, ...) {
+  char buf[512];
+  va_list ap;
+
+  if (level < ctx->log_level)
+    return;
+  va_start(ap, fmt);
+  vsnprintf(buf, sizeof buf, fmt, ap);
+  va_end(ap);
+  ctx->log(level, buf, ctx->log_user);
+}
+
+int rg__fail(rg_context *ctx, int code, const char *fmt, ...) {
+  va_list ap;
+
+  va_start(ap, fmt);
+  vsnprintf(ctx->last_error, sizeof ctx->last_error, fmt, ap);
+  va_end(ap);
+  rg__log(ctx, RG_LOG_ERROR, "%s", ctx->last_error);
+  return code;
+}
+
+const char *rg_last_error(const rg_context *ctx) { return ctx->last_error; }
+
+rg_context *rg_create(const rg_config *config) {
+  rg_config cfg;
+  rg_context *ctx;
+  size_t n;
+
+  rg_config_init(&cfg);
+  if (config) {
+    n = config->struct_size < sizeof cfg ? config->struct_size : sizeof cfg;
+    memcpy(&cfg, config, n);
+  }
+
+  if (!cfg.allocator.alloc || !cfg.allocator.realloc || !cfg.allocator.free) {
+    rg_config defaults;
+    rg_config_init(&defaults);
+    cfg.allocator = defaults.allocator;
+  }
+  if (!cfg.log)
+    cfg.log = default_log;
+  if (cfg.display_scale <= 0.0f)
+    cfg.display_scale = 1.0f;
+
+  ctx = cfg.allocator.alloc(sizeof *ctx, cfg.allocator.user);
+  if (!ctx)
+    return NULL;
+  memset(ctx, 0, sizeof *ctx);
+
+  ctx->alloc = cfg.allocator;
+  ctx->log = cfg.log;
+  ctx->log_user = cfg.log_user;
+  ctx->log_level = cfg.log_level;
+  ctx->viewport_w = cfg.viewport_w;
+  ctx->viewport_h = cfg.viewport_h;
+  ctx->display_scale = cfg.display_scale;
+
+  rg__log(ctx, RG_LOG_DEBUG, "clay minimum memory: %zu bytes",
+          rg__clay_min_memory());
+  rg__log(ctx, RG_LOG_INFO, "context created (%dx%d @ %.2fx)",
+          (int)ctx->viewport_w, (int)ctx->viewport_h,
+          (double)ctx->display_scale);
+  return ctx;
+}
+
+void rg_destroy(rg_context *ctx) {
+  rg_allocator a;
+
+  if (!ctx)
+    return;
+  rg__lua_close(ctx);
+  rg__log(ctx, RG_LOG_INFO, "context destroyed");
+  a = ctx->alloc;
+  a.free(ctx, sizeof *ctx, a.user);
+}
diff --git a/src/internal.h b/src/internal.h
new file mode 100644
index 0000000..c1f5da5
--- /dev/null
+++ b/src/internal.h
@@ -0,0 +1,33 @@
+#ifndef RG_INTERNAL_H
+#define RG_INTERNAL_H
+
+
+#include "../include/regolith.h"
+
+#if defined(__GNUC__)
+  #define RG_PRINTF(f, a) __attribute__((format(printf, f, a)))
+#else
+  #define RG_PRINTF(f, a)
+#endif
+
+struct lua_State;
+
+struct rg_context {
+  rg_allocator alloc;
+  rg_log_fn log;
+  void* log_user;
+  int32_t log_level;
+  int32_t viewport_w;
+  int32_t viewport_h;
+  float display_scale;
+  char last_error[256];
+  struct lua_State* L;
+};
+
+void rg__log(rg_context* ctx, int32_t level, const char* fmt, ...) RG_PRINTF(3, 4);
+int rg__fail(rg_context* ctx, int code, const char* fmt, ...) RG_PRINTF(3, 4);
+
+size_t rg__clay_min_memory(void);
+void rg__lua_close(rg_context* ctx);
+
+#endif
diff --git a/src/layout_clay.c b/src/layout_clay.c
new file mode 100644
index 0000000..ec2b31c
--- /dev/null
+++ b/src/layout_clay.c
@@ -0,0 +1,10 @@
+
+#define CLAY_IMPLEMENTATION
+#include "../third_party/clay/clay.h"
+
+#include "internal.h"
+
+size_t rg__clay_min_memory(void)
+{
+  return Clay_MinMemorySize(); 
+}
diff --git a/src/lua_module.c b/src/lua_module.c
new file mode 100644
index 0000000..2caa4c3
--- /dev/null
+++ b/src/lua_module.c
@@ -0,0 +1,72 @@
+#include "internal.h"
+#include "../include/regolith_lua.h"
+
+#include <string.h>
+
+#include <lauxlib.h>
+#include <lua.h>
+#include <lualib.h>
+
+static void *lua_alloc(void *ud, void *ptr, size_t osize, size_t nsize)
+{
+    rg_context *ctx = ud;
+    rg_allocator *a = &ctx->alloc;
+
+    if (nsize == 0) {
+        if (ptr) a->free(ptr, osize, a->user);
+        return NULL;
+    }
+    if (!ptr) return a->alloc(nsize, a->user);
+    return a->realloc(ptr, osize, nsize, a->user);
+}
+
+static int on_panic(lua_State *L)
+{
+    void *ud;
+    const char *msg = lua_tostring(L, -1);
+
+    lua_getallocf(L, &ud);
+    rg__log(ud, RG_LOG_ERROR, "lua panic: %s", msg ? msg : "unknown");
+    return 0;
+}
+
+int rg_lua_open(rg_context *ctx)
+{
+    lua_State *L;
+
+    if (ctx->L) return RG_OK;
+    L = lua_newstate(lua_alloc, ctx);
+    if (!L) return rg__fail(ctx, RG_ERR_NO_MEMORY, "could not create lua state");
+    lua_atpanic(L, on_panic);
+    luaL_openlibs(L);
+    ctx->L = L;
+    rg__log(ctx, RG_LOG_INFO, "lua opened (%s)", LUA_VERSION);
+    return RG_OK;
+}
+
+void rg__lua_close(rg_context *ctx)
+{
+    if (!ctx->L) return;
+    lua_close(ctx->L);
+    ctx->L = NULL;
+}
+
+int rg_lua_dostring(rg_context *ctx, const char *code, const char *chunk_name)
+{
+    lua_State *L = ctx->L;
+
+    if (!L) return rg__fail(ctx, RG_ERR_STATE, "lua is not open");
+    if (luaL_loadbuffer(L, code, strlen(code), chunk_name ? chunk_name : "=string") != LUA_OK ||
+        lua_pcall(L, 0, 0, 0) != LUA_OK) {
+        const char *msg = lua_tostring(L, -1);
+        int rc = rg__fail(ctx, RG_ERR_LUA, "%s", msg ? msg : "unknown lua error");
+        lua_pop(L, 1);
+        return rc;
+    }
+    return RG_OK;
+}
+
+struct lua_State *rg_lua_state(rg_context *ctx)
+{
+    return ctx->L;
+}
diff --git a/src/text_stb.c b/src/text_stb.c
new file mode 100644
index 0000000..fe23f38
--- /dev/null
+++ b/src/text_stb.c
@@ -0,0 +1,6 @@
+#define STB_RECT_PACK_IMPLEMENTATION
+#include "../third_party/stb/stb_rect_pack.h"
+#define STB_TRUETYPE_IMPLEMENTATION
+#include "../third_party/stb/stb_truetype.h"
+
+#include "internal.h"
diff --git a/tests/smoke.c b/tests/smoke.c
new file mode 100644
index 0000000..e568a92
--- /dev/null
+++ b/tests/smoke.c
@@ -0,0 +1,70 @@
+#include "../include/regolith.h"
+#include "../include/regolith_lua.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct counter {
+  size_t live;
+  size_t peak;
+} counter;
+
+static void track(counter *c, size_t add, size_t sub) {
+  c->live = c->live + add - sub;
+  if (c->live > c->peak)
+    c->peak = c->live;
+}
+
+static void *c_alloc(size_t size, void *user) {
+  void *p = malloc(size);
+  if (p)
+    track(user, size, 0);
+  return p;
+}
+
+static void *c_realloc(void *ptr, size_t old_size, size_t new_size,
+                       void *user) {
+  void *p = realloc(ptr, new_size);
+  if (p)
+    track(user, new_size, old_size);
+  return p;
+}
+
+static void c_free(void *ptr, size_t size, void *user) {
+  track(user, 0, size);
+  free(ptr);
+}
+
+int main(void) {
+  counter c = {0, 0};
+  rg_config cfg;
+  rg_context *ctx;
+  int rc;
+
+  rg_config_init(&cfg);
+  cfg.allocator.alloc = c_alloc;
+  cfg.allocator.realloc = c_realloc;
+  cfg.allocator.free = c_free;
+  cfg.allocator.user = &c;
+
+  ctx = rg_create(&cfg);
+  if (!ctx)
+    return 1;
+
+  rc = rg_lua_open(ctx);
+  if (rc == RG_OK)
+    rc = rg_lua_dostring(ctx, "print('hello from ' .. _VERSION)", "=smoke");
+  if (rc == RG_OK)
+    rc = rg_lua_dostring(ctx, "this is not lua", "=smoke_bad") == RG_ERR_LUA
+             ? RG_OK
+             : RG_ERR_GENERIC;
+
+  printf("regolith %s, peak %zu bytes\n", rg_version(), c.peak);
+  rg_destroy(ctx);
+
+  if (c.live != 0) {
+    printf("leak: %zu bytes still live\n", c.live);
+    return 1;
+  }
+  return rc == RG_OK ? 0 : 1;
+}
diff --git a/tests/smoke_sdl3.c b/tests/smoke_sdl3.c
new file mode 100644
index 0000000..e92eb6b
--- /dev/null
+++ b/tests/smoke_sdl3.c
@@ -0,0 +1,9 @@
+#include <SDL3/SDL.h>
+#include <stdio.h>
+
+int main(void)
+{
+    int v = SDL_GetVersion();
+    printf("SDL %d.%d.%d\n", SDL_VERSIONNUM_MAJOR(v), SDL_VERSIONNUM_MINOR(v), SDL_VERSIONNUM_MICRO(v));
+    return 0;
+}