flask/flaskr/static/style.css

html {
  font-family: 'Roboto', sans-serif;
  background: #FEFAE0;
  padding: 1rem;
}

body {
  max-width: 960px;
  margin: 0 auto;
  background: white;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  border-radius: 8px;
}

h1, h2, h3, h4, h5, h6 {
  font-family: 'Roboto', sans-serif;
  color: #377ba8;
  margin: 1rem 0;
}

a {
  color: #377ba8;
  text-decoration: none;
}

hr {
  border: none;
  border-top: 1px solid #E0E5B6;
}

nav {
  background: #CCD5AE;
  display: flex;
  align-items: center;
  padding: 0 0.5rem;
  border-radius: 8px;
}

nav h1 {
  flex: auto;
  margin: 0;
}

nav h1 a {
  text-decoration: none;
  padding: 0.25rem 0.5rem;
  color: #377ba8;
}

nav ul  {
  display: flex;
  list-style: none;
  margin: 0;
  padding: 0;
  align-items: center;
}

nav ul li a, nav ul li span, header .action {
  display: block;
  padding: 0.5rem;
  color: #377ba8;
}

.content {
  padding: 0 1rem 1rem;
}

.content > header {
  border-bottom: 1px solid #E0E5B6;
  display: flex;
  align-items: flex-end;
}

.content > header h1 {
  flex: auto;
  margin: 1rem 0 0.25rem 0;
}

.flash {
  margin: 1em 0;
  padding: 1em;
  background: #FAEDCE;
  border: 1px solid #377ba8;
  border-radius: 4px;
}

.post > header {
  display: flex;
  align-items: flex-end;
  font-size: 0.85em;
}

.post > header > div:first-of-type {
  flex: auto;
}

.post > header h1 {
  font-size: 1.5em;
  margin-bottom: 0;
}

.post .about {
  color: slategray;
  font-style: italic;
}

.post .body {
  white-space: pre-line;
}

.content:last-child {
  margin-bottom: 0;
}

.content form {
  margin: 1em 0;
  display: flex;
  flex-direction: column;
}

.content label {
  font-weight: bold;
  margin-bottom: 0.5em;
}

.content input, .content textarea {
  margin-bottom: 1em;
  background: #f5f5f5;
  border: 1px solid #ccc;
  padding: 0.5em;
  border-radius: 4px;
}

.content textarea {
  min-height: 12em;
  resize: vertical;
}

input.danger {
  color: #cc2f2e;
}

input[type=submit] {
  align-self: start;
  min-width: 10em;
  background-color: #377ba8;
  color: white;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  transition: background-color 0.3s;
}

input[type=submit]:hover {
  background-color: #2c5f8a;
}

#theme-toggle {
  position: relative;
  width: 50px;
  height: 25px;
  background: #ccc;
  border-radius: 25px;
  cursor: pointer;
  transition: background 0.3s;
  display: flex;
  align-items: center;
  justify-content: center;
}

#theme-toggle:before {
  content: '\f186'; /* FontAwesome Unicode for moon */
  font-family: 'FontAwesome';
  font-weight: 900;
  position: absolute;
  top: 2px;
  left: 2px;
  width: 21px;
  height: 21px;
  border-radius: 50%;
  transition: transform 0.3s, content 0.3s;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  color: #333;
}

html.dark-mode {
  background: #555555;
}

body.dark-mode #theme-toggle {
  background: #4d4d4d;
}

body.dark-mode #theme-toggle:before {
  transform: translateX(25px);
  content: '\f185'; /* FontAwesome Unicode for sun */
  color: #e0e0e0;
}

body.dark-mode {
  background: #121212;
  color: #e0e0e0;
}

body.dark-mode a {
  color: #bb86fc;
}

body.dark-mode nav {
  background: #333;
}

body.dark-mode .flash {
  background: #333;
  border-color: #bb86fc;
}

body.dark-mode .post .about {
  color: #999;
}

body.dark-mode .content input, 
body.dark-mode .content textarea {
  background: #333;
  color: #e0e0e0;
  border: 1px solid #555;
}