diff --git a/src/humanize/filesize.py b/src/humanize/filesize.py
index 754a9f3..694e264 100644
--- a/src/humanize/filesize.py
+++ b/src/humanize/filesize.py
@@ -10,12 +10,20 @@ suffixes = {
 
 
 def naturalsize(value, binary=False, gnu=False, format="%.1f"):
-    """Format a number of byteslike a human readable filesize (eg. 10 kB).  By
-    default, decimal suffixes (kB, MB) are used.  Passing binary=true will use
-    binary suffixes (KiB, MiB) are used and the base will be 2**10 instead of
-    10**3.  If ``gnu`` is True, the binary argument is ignored and GNU-style
-    (ls -sh style) prefixes are used (K, M) with the 2**10 definition.
-    Non-gnu modes are compatible with jinja2's ``filesizeformat`` filter."""
+    """Format a number of bytes like a human readable filesize (eg. 10 kB).
+
+    By default, decimal suffixes (kB, MB) are used.
+
+    Non-gnu modes are compatible with jinja2's ``filesizeformat`` filter.
+
+    Args:
+        value (int, float, string): Integer to convert.
+        binary (Boolean): If `True`, uses binary suffixes (KiB, MiB) with base 2**10
+        instead of 10**3.
+        gnu (Boolean): If `True`, the binary argument is ignored and GNU-style
+        (`ls -sh` style) prefixes are used (K, M) with the 2**10 definition.
+        format (str): Custom formatter.
+    """
     if gnu:
         suffix = suffixes["gnu"]
     elif binary:
@@ -25,19 +33,20 @@ def naturalsize(value, binary=False, gnu=False, format="%.1f"):
 
     base = 1024 if (gnu or binary) else 1000
     bytes = float(value)
+    abs_bytes = abs(bytes)
 
-    if bytes == 1 and not gnu:
-        return "1 Byte"
-    elif bytes < base and not gnu:
+    if abs_bytes == 1 and not gnu:
+        return "%d Byte" % bytes
+    elif abs_bytes < base and not gnu:
         return "%d Bytes" % bytes
-    elif bytes < base and gnu:
+    elif abs_bytes < base and gnu:
         return "%dB" % bytes
 
     for i, s in enumerate(suffix):
         unit = base ** (i + 2)
-        if bytes < unit and not gnu:
+        if abs_bytes < unit and not gnu:
             return (format + " %s") % ((base * bytes / unit), s)
-        elif bytes < unit and gnu:
+        elif abs_bytes < unit and gnu:
             return (format + "%s") % ((base * bytes / unit), s)
     if gnu:
         return (format + "%s") % ((base * bytes / unit), s)

Negative Sizes Only Show In Bytes
When using `naturalsize` with negative values (I wish to display a change in file size), you only get bytes:

```python
>>> In[4] import humanize
>>> In[5] humanize.naturalsize(123456)
>>> Out[5]: '123.5 kB'
>>> In[6] humanize.naturalsize(-123456)
>>> Out[6]: '-123456 Bytes'
````

Is it possible to get these values shown in the same manner as positive values?
diff --git a/tests/test_filesize.py b/tests/test_filesize.py
index 959ce88..871c61a 100644
--- a/tests/test_filesize.py
+++ b/tests/test_filesize.py
@@ -31,5 +31,9 @@ import pytest
         ([10 ** 26 * 30, True, False, "%.3f"], "2481.542 YiB"),
     ],
 )
-def test_naturaltime_minimum_unit_default(test_args, expected):
+def test_naturalsize(test_args, expected):
     assert humanize.naturalsize(*test_args) == expected
+
+    args_with_negative = test_args
+    args_with_negative[0] *= -1
+    assert humanize.naturalsize(*args_with_negative) == "-" + expected

pip install -e .[tests]
parse_log_pytest
requirements.txt
pytest pytest-cov
3.7
pytest --no-header -rA --tb=line --color=no -p no:cacheprovider -W ignore::DeprecationWarning
certifi @ file:///croot/certifi_1671487769961/work/certifi
coverage==7.2.7
exceptiongroup==1.2.2
freezegun==1.5.1
-e git+https://github.com/jmoiron/humanize.git@aaca29f35306c48c9965047ac5d39807a33652a7#egg=humanize
importlib-metadata==6.7.0
iniconfig==2.0.0
packaging==24.0
pluggy==1.2.0
pytest==7.4.4
pytest-cov==4.1.0
python-dateutil==2.9.0.post0
six==1.17.0
tomli==2.0.1
typing_extensions==4.7.1
zipp==3.15.0

name: humanize
channels:
  - defaults
  - https://repo.anaconda.com/pkgs/main
  - https://repo.anaconda.com/pkgs/r
  - conda-forge
dependencies:
  - _libgcc_mutex=0.1=main
  - _openmp_mutex=5.1=1_gnu
  - ca-certificates=2025.2.25=h06a4308_0
  - certifi=2022.12.7=py37h06a4308_0
  - ld_impl_linux-64=2.40=h12ee557_0
  - libffi=3.4.4=h6a678d5_1
  - libgcc-ng=11.2.0=h1234567_1
  - libgomp=11.2.0=h1234567_1
  - libstdcxx-ng=11.2.0=h1234567_1
  - ncurses=6.4=h6a678d5_0
  - openssl=1.1.1w=h7f8727e_0
  - pip=22.3.1=py37h06a4308_0
  - python=3.7.16=h7a1cb2a_0
  - readline=8.2=h5eee18b_0
  - setuptools=65.6.3=py37h06a4308_0
  - sqlite=3.45.3=h5eee18b_0
  - tk=8.6.14=h39e8969_0
  - wheel=0.38.4=py37h06a4308_0
  - xz=5.6.4=h5eee18b_1
  - zlib=1.2.13=h5eee18b_1
  - pip:
      - coverage==7.2.7
      - exceptiongroup==1.2.2
      - freezegun==1.5.1
      - humanize==2.0.0
      - importlib-metadata==6.7.0
      - iniconfig==2.0.0
      - packaging==24.0
      - pluggy==1.2.0
      - pytest==7.4.4
      - pytest-cov==4.1.0
      - python-dateutil==2.9.0.post0
      - six==1.17.0
      - tomli==2.0.1
      - typing-extensions==4.7.1
      - zipp==3.15.0
prefix: /opt/conda/envs/humanize

tests/test_filesize.py::test_naturalsize[test_args1-3.0 tests/test_filesize.py::test_naturalsize[test_args2-3.0 tests/test_filesize.py::test_naturalsize[test_args3-3.0 tests/test_filesize.py::test_naturalsize[test_args4-3.0 tests/test_filesize.py::test_naturalsize[test_args6-2.9 tests/test_filesize.py::test_naturalsize[test_args7-2.9 tests/test_filesize.py::test_naturalsize[test_args9-2.9K] tests/test_filesize.py::test_naturalsize[test_args10-2.9M] tests/test_filesize.py::test_naturalsize[test_args11-1.0K] tests/test_filesize.py::test_naturalsize[test_args12-2481.5Y] tests/test_filesize.py::test_naturalsize[test_args13-2481.5 tests/test_filesize.py::test_naturalsize[test_args14-3000.0 tests/test_filesize.py::test_naturalsize[test_args15-1 tests/test_filesize.py::test_naturalsize[test_args16-3.14 tests/test_filesize.py::test_naturalsize[test_args17-2.930K] tests/test_filesize.py::test_naturalsize[test_args18-3G] tests/test_filesize.py::test_naturalsize[test_args19-2481.542
tests/test_filesize.py::test_naturalsize[test_args0-300 tests/test_filesize.py::test_naturalsize[test_args5-300 tests/test_filesize.py::test_naturalsize[test_args8-300B]
src/humanize/filesize.py
src/humanize/filesize.py