diff --git a/tools/themes/collection.go b/tools/themes/collection.go
index 9432894d1..c82321680 100644
--- a/tools/themes/collection.go
+++ b/tools/themes/collection.go
@@ -4,16 +4,23 @@ package themes
 
 import (
 	"archive/zip"
+	"bufio"
 	"encoding/json"
 	"errors"
 	"fmt"
 	"io"
 	"io/fs"
 	"kitty/tools/utils"
+	"kitty/tools/utils/style"
 	"net/http"
 	"os"
+	"path"
 	"path/filepath"
+	"regexp"
+	"strings"
 	"time"
+
+	"golang.org/x/exp/maps"
 )
 
 var _ = fmt.Print
@@ -117,3 +124,192 @@ func fetch_cached(name, url string, max_cache_age time.Duration) (string, error)
 func FetchCached(max_cache_age time.Duration) (string, error) {
 	return fetch_cached("kitty-themes", "https://codeload.github.com/kovidgoyal/kitty-themes/zip/master", max_cache_age)
 }
+
+type ThemeMetadata struct {
+	Name         string `json:"name"`
+	Filepath     string `json:"file"`
+	Is_dark      bool   `json:"is_dark"`
+	Num_settings int    `json:"num_settings"`
+	Blurb        string `json:"blurb"`
+	License      string `json:"license"`
+	Upstream     string `json:"upstream"`
+	Author       string `json:"author"`
+}
+
+func parse_theme_metadata(raw string) *ThemeMetadata {
+	scanner := bufio.NewScanner(strings.NewReader(raw))
+	var in_metadata, in_blurb, finished_metadata bool
+	ans := ThemeMetadata{}
+	settings := utils.NewSet[string]()
+	for scanner.Scan() {
+		line := strings.TrimSpace(scanner.Text())
+		if line == "" {
+			continue
+		}
+		is_block := strings.HasPrefix(line, "## ")
+		if in_metadata && !is_block {
+			finished_metadata = true
+		}
+		if finished_metadata {
+			if line[0] != '#' {
+				key, val, found := strings.Cut(line, " ")
+				if found {
+					settings.Add(key)
+					if key == "background" {
+						val = strings.TrimSpace(val)
+						if val != "" {
+							bg, err := style.ParseColor(val)
+							if err == nil {
+								ans.Is_dark = utils.Max(bg.Red, bg.Green, bg.Green) < 115
+							}
+						}
+					}
+				}
+			}
+			continue
+		}
+		if !in_metadata && is_block {
+			in_metadata = true
+		}
+		if !in_metadata {
+			continue
+		}
+		line = line[3:]
+		if in_blurb {
+			ans.Blurb += " " + line
+			continue
+		}
+		key, val, found := strings.Cut(line, ":")
+		if !found {
+			continue
+		}
+		key = strings.TrimSpace(strings.ToLower(key))
+		val = strings.TrimSpace(val)
+		switch key {
+		case "name":
+			ans.Name = val
+		case "author":
+			ans.Author = val
+		case "upstream":
+			ans.Upstream = val
+		case "blurb":
+			ans.Blurb = val
+			in_blurb = true
+		case "license":
+			ans.License = val
+		}
+	}
+	ans.Num_settings = settings.Len()
+	return &ans
+}
+
+type Theme struct {
+	metadata *ThemeMetadata
+
+	code            string
+	zip_reader      *zip.File
+	is_user_defined bool
+}
+
+type Themes struct {
+	name_map  map[string]*Theme
+	index_map []string
+}
+
+var camel_case_pat = (&utils.Once[*regexp.Regexp]{Run: func() *regexp.Regexp {
+	return regexp.MustCompile(`[a-z][A-Z]`)
+}}).Get
+
+func theme_name_from_file_name(fname string) string {
+	fname = fname[:len(fname)-len(path.Ext(fname))]
+	fname = strings.ReplaceAll(fname, "_", " ")
+	fname = camel_case_pat().ReplaceAllString(fname, "$1 $2")
+	return strings.Join(utils.Map(strings.Split(fname, " "), strings.Title), " ")
+}
+
+func (self *Themes) add_from_dir(dirpath string) error {
+	entries, err := os.ReadDir(dirpath)
+	if err != nil {
+		if errors.Is(err, fs.ErrNotExist) {
+			err = nil
+		}
+		return err
+	}
+	for _, e := range entries {
+		if !e.IsDir() && strings.HasSuffix(e.Name(), ".conf") {
+			confb, err := os.ReadFile(e.Name())
+			if err != nil {
+				return err
+			}
+			conf := utils.UnsafeBytesToString(confb)
+			m := parse_theme_metadata(conf)
+			if m.Name == "" {
+				m.Name = theme_name_from_file_name(e.Name())
+			}
+			t := Theme{metadata: m, is_user_defined: true, code: conf}
+			self.name_map[m.Name] = &t
+		}
+	}
+	return nil
+}
+
+func (self *Themes) add_from_zip_file(zippath string) error {
+	r, err := zip.OpenReader(zippath)
+	if err != nil {
+		return err
+	}
+	name_map := make(map[string]*zip.File, len(r.File))
+	var themes []ThemeMetadata
+	theme_dir := ""
+	for _, file := range r.File {
+		name_map[file.Name] = file
+		if path.Base(file.Name) == "themes.json" {
+			theme_dir = path.Dir(file.Name)
+			fr, err := file.Open()
+			if err != nil {
+				return fmt.Errorf("Error while opening %s from the ZIP file: %w", file.Name, err)
+			}
+			defer fr.Close()
+			raw, err := io.ReadAll(fr)
+			if err != nil {
+				return fmt.Errorf("Error while reading %s from the ZIP file: %w", file.Name, err)
+			}
+			err = json.Unmarshal(raw, &themes)
+			if err != nil {
+				return fmt.Errorf("Error while decoding %s: %w", file.Name, err)
+			}
+		}
+	}
+	if theme_dir == "" {
+		return fmt.Errorf("No themes.json found in ZIP file")
+	}
+	for _, theme := range themes {
+		key := path.Join(theme_dir, theme.Filepath)
+		f := name_map[key]
+		if f != nil {
+			t := Theme{metadata: &theme, zip_reader: f}
+			self.name_map[theme.Name] = &t
+		}
+	}
+	return nil
+}
+
+func LoadThemes(cache_age_in_days time.Duration, ignore_no_cache bool) (*Themes, error) {
+	zip_path, err := FetchCached(cache_age_in_days * time.Hour * 24)
+	ans := Themes{name_map: make(map[string]*Theme)}
+	if err != nil {
+		if !errors.Is(err, ErrNoCacheFound) || ignore_no_cache {
+			return nil, err
+		}
+	} else {
+		if err = ans.add_from_zip_file(zip_path); err != nil {
+			return nil, err
+		}
+	}
+	if err = ans.add_from_dir(filepath.Join(utils.ConfigDir(), "themes")); err != nil {
+		return nil, err
+	}
+	ans.index_map = maps.Keys(ans.name_map)
+	ans.index_map = utils.StableSortWithKey(ans.index_map, strings.ToLower)
+	return &ans, nil
+}
diff --git a/tools/utils/misc.go b/tools/utils/misc.go
index ca5b8702b..b63250f05 100644
--- a/tools/utils/misc.go
+++ b/tools/utils/misc.go
@@ -57,6 +57,14 @@ func Filter[T any](s []T, f func(x T) bool) []T {
 	return ans
 }
 
+func Map[T any](s []T, f func(x T) T) []T {
+	ans := make([]T, 0, len(s))
+	for _, x := range s {
+		ans = append(ans, f(x))
+	}
+	return ans
+}
+
 func Sort[T any](s []T, less func(a, b T) bool) []T {
 	sort.Slice(s, func(i, j int) bool { return less(s[i], s[j]) })
 	return s