body.dark-theme {
    --bg-color: #121212;
    --text-color: #e0e0e0;
    --header-bg: #1e1e1e;
    --card-bg: #1e1e1e;
    --border-color: #333333;
    --highlight-color: #0d6efd;
    --highlight-hover: #0b5ed7;
    --error-color: #ff6b6b;
    --success-color: #43cc76;
}

body.dark-theme {
    background-color: var(--bg-color);
    color: var(--text-color);
}

.dark-theme .app-header {
    background-color: var(--header-bg);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
}

.dark-theme .login-form,
.dark-theme .file-selector,
.dark-theme .plots-container {
    background-color: var(--card-bg);
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.4);
}

.dark-theme .form-group input {
    border: 1px solid var(--border-color);
    background-color: #252525;
    color: var(--text-color);
}

.dark-theme .login-button {
    background-color: var(--highlight-color);
    color: white;
}

.dark-theme .error-message {
    color: var(--error-color);
    background-color: rgba(255, 107, 107, 0.1);
}

.dark-theme .file-item {
    background-color: #252525;
    border: 1px solid var(--border-color);
}

.dark-theme .file-item:hover {
    border-color: var(--highlight-color);
}

.dark-theme .file-item.selected {
    border-color: var(--highlight-color);
    background-color: rgba(13, 110, 253, 0.2);
}

.dark-theme .file-date {
    color: #adb5bd;
}

.dark-theme .chart-container {
    background-color: #252525;
    border: 1px solid var(--border-color);
}

.dark-theme .loading,
.dark-theme .no-files {
    color: #adb5bd;
}

.dark-theme .slider {
    background-color: #555;
}

.dark-theme .slider:before {
    background-color: white;
}

.dark-theme input:checked + .slider {
    background-color: var(--highlight-color);
}

.dark-theme .logout-btn {
    background-color: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-color);
}

.dark-theme .logout-btn:hover {
    background-color: rgba(255, 255, 255, 0.05);
}