diff --git a/blacklayer.c b/blacklayer.c
index 72c7682..eff8ebd 100644
--- a/blacklayer.c
+++ b/blacklayer.c
@@ -5,19 +5,39 @@
 #include <string.h>
 #include <stdio.h>
 
+/* ---------- default black color ---------- */
+static const GdkRGBA DEFAULT_COLOR = { 0.0, 0.0, 0.0, 1.0 };
+
 static GdkPixbufAnimation *anim;
 static GdkPixbufAnimationIter *iter;
 static int SW, SH;
 
 /* ---------- draw callback ---------- */
 static gboolean draw_cb(GtkWidget *w, cairo_t *cr, gpointer data) {
+
+    /* background black */
+    cairo_set_source_rgba(
+        cr,
+        DEFAULT_COLOR.red,
+        DEFAULT_COLOR.green,
+        DEFAULT_COLOR.blue,
+        DEFAULT_COLOR.alpha
+    );
+    cairo_paint(cr);
+
+    if (!iter)
+        return FALSE;
+
     GdkPixbuf *frame = gdk_pixbuf_animation_iter_get_pixbuf(iter);
+    if (!frame)
+        return FALSE;
+
     int RW = gdk_pixbuf_get_width(frame);
     int RH = gdk_pixbuf_get_height(frame);
 
     double scale_w = (double)SW / RW;
     double scale_h = (double)SH / RH;
-    double scale = scale_w > scale_h ? scale_w : scale_h;
+    double scale = (scale_w > scale_h) ? scale_w : scale_h;
 
     int NW = RW * scale;
     int NH = RH * scale;
@@ -25,16 +45,21 @@ static gboolean draw_cb(GtkWidget *w, cairo_t *cr, gpointer data) {
     int x = (SW - NW) / 2;
     int y = (SH - NH) / 2;
 
+    cairo_save(cr);
     cairo_translate(cr, x, y);
     cairo_scale(cr, scale, scale);
     gdk_cairo_set_source_pixbuf(cr, frame, 0, 0);
     cairo_paint(cr);
+    cairo_restore(cr);
 
     return FALSE;
 }
 
 /* ---------- frame timer ---------- */
 static gboolean tick_cb(gpointer data) {
+    if (!iter)
+        return TRUE;
+
     gdk_pixbuf_animation_iter_advance(iter, NULL);
     gtk_widget_queue_draw(GTK_WIDGET(data));
     return TRUE;
@@ -45,8 +70,10 @@ static int get_monitor_id(const char *name) {
     char cmd[256];
     snprintf(cmd, sizeof(cmd),
         "hyprctl -j monitors | jq -r '.[] | select(.name==\"%s\") | .id'", name);
+
     FILE *fp = popen(cmd, "r");
     if (!fp) return -1;
+
     int id = -1;
     fscanf(fp, "%d", &id);
     pclose(fp);
@@ -57,16 +84,19 @@ static int get_monitor_id(const char *name) {
 static char *get_resource(void) {
     static char line[512];
     char path[512];
+
     snprintf(path, sizeof(path),
         "%s/.config/blacklayer/blacklayer.conf", getenv("HOME"));
+
     FILE *f = fopen(path, "r");
     if (!f) return NULL;
+
     while (fgets(line, sizeof(line), f)) {
         if (!strncmp(line, "resource=", 9)) {
             char *r = line + 9;
             r[strcspn(r, "\n")] = 0;
             fclose(f);
-            return r;
+            return (*r) ? r : NULL;
         }
     }
     fclose(f);
@@ -86,7 +116,7 @@ int main(int argc, char **argv) {
     gtk_layer_set_anchor(GTK_WINDOW(win), GTK_LAYER_SHELL_EDGE_LEFT, TRUE);
     gtk_layer_set_anchor(GTK_WINDOW(win), GTK_LAYER_SHELL_EDGE_RIGHT, TRUE);
 
-    /* monitor */
+    /* ---------- monitor ---------- */
     GdkRectangle geo = {0};
     if (argc > 1) {
         int id = get_monitor_id(argv[1]);
@@ -100,7 +130,7 @@ int main(int argc, char **argv) {
         }
     }
 
-    if (!geo.width) {
+    if (!geo.width || !geo.height) {
         GdkScreen *s = gdk_screen_get_default();
         geo.width = gdk_screen_get_width(s);
         geo.height = gdk_screen_get_height(s);
@@ -109,23 +139,27 @@ int main(int argc, char **argv) {
     SW = geo.width;
     SH = geo.height;
 
-    char *res = get_resource();
-    if (!res) return 0;
-
-    anim = gdk_pixbuf_animation_new_from_file(res, NULL);
-    iter = gdk_pixbuf_animation_get_iter(anim, NULL);
-
     GtkWidget *area = gtk_drawing_area_new();
     gtk_widget_set_size_request(area, SW, SH);
     gtk_container_add(GTK_CONTAINER(win), area);
 
     g_signal_connect(area, "draw", G_CALLBACK(draw_cb), NULL);
 
-    g_timeout_add(
-        gdk_pixbuf_animation_iter_get_delay_time(iter),
-        tick_cb,
-        area
-    );
+    /* ---------- resource load ---------- */
+    char *res = get_resource();
+    if (res) {
+        anim = gdk_pixbuf_animation_new_from_file(res, NULL);
+        if (anim)
+            iter = gdk_pixbuf_animation_get_iter(anim, NULL);
+
+        if (iter) {
+            g_timeout_add(
+                gdk_pixbuf_animation_iter_get_delay_time(iter),
+                tick_cb,
+                area
+            );
+        }
+    }
 
     gtk_widget_show_all(win);
     gtk_main();