diff --git a/themes/modern/css/theme.css b/themes/modern/css/theme.css
new file mode 100644
index 0000000..f8361c5
--- /dev/null
+++ b/themes/modern/css/theme.css
@@ -0,0 +1,180 @@
+/* Modern Theme Styles */
+
+:root {
+    --primary-color: #4361ee;
+    --secondary-color: #3f37c9;
+    --accent-color: #4895ef;
+    --light-color: #f8f9fa;
+    --dark-color: #212529;
+    --success-color: #4bb543;
+    --warning-color: #f9c74f;
+    --danger-color: #ef476f;
+    --border-radius: 0.5rem;
+}
+
+/* General Styles */
+body.modern-theme {
+    background-color: #f5f7fa;
+    color: #333;
+    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
+}
+
+/* Navigation */
+.menu-container {
+    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
+    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
+    padding: 0.5rem 1rem;
+}
+
+.menu-left {
+    display: flex;
+    align-items: center;
+}
+
+.menu-right {
+    display: flex;
+    align-items: center;
+    justify-content: flex-end;
+}
+
+/* Cards */
+.card {
+    border: none;
+    border-radius: var(--border-radius);
+    box-shadow: 0 2px 15px rgba(0, 0, 0, 0.05);
+    transition: transform 0.2s, box-shadow 0.2s;
+    margin-bottom: 1.5rem;
+}
+
+.card:hover {
+    transform: translateY(-2px);
+    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
+}
+
+.card-header {
+    background-color: white;
+    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
+    font-weight: 600;
+}
+
+/* Buttons */
+.btn-primary {
+    background-color: var(--primary-color);
+    border-color: var(--primary-color);
+    border-radius: var(--border-radius);
+    padding: 0.375rem 1rem;
+    font-weight: 500;
+    transition: all 0.2s;
+}
+
+.btn-primary:hover {
+    background-color: var(--secondary-color);
+    border-color: var(--secondary-color);
+    transform: translateY(-1px);
+}
+
+/* Forms */
+.form-control {
+    border-radius: var(--border-radius);
+    border: 1px solid #e1e5eb;
+    padding: 0.5rem 0.75rem;
+}
+
+.form-control:focus {
+    border-color: var(--accent-color);
+    box-shadow: 0 0 0 0.2rem rgba(67, 97, 238, 0.25);
+}
+
+/* Tables */
+.table {
+    background-color: white;
+    border-radius: var(--border-radius);
+    overflow: hidden;
+}
+
+.table thead th {
+    background-color: #f8f9fa;
+    border-bottom: 2px solid #e9ecef;
+    font-weight: 600;
+    text-transform: uppercase;
+    font-size: 0.75rem;
+    letter-spacing: 0.5px;
+}
+
+/* Alerts */
+.alert {
+    border-radius: var(--border-radius);
+    border: none;
+    padding: 1rem 1.25rem;
+}
+
+.alert-success {
+    background-color: rgba(75, 181, 67, 0.1);
+    color: var(--success-color);
+}
+
+.alert-warning {
+    background-color: rgba(249, 199, 79, 0.1);
+    color: #c9a227;
+}
+
+.alert-danger {
+    background-color: rgba(239, 71, 111, 0.1);
+    color: var(--danger-color);
+}
+
+/* Theme Switcher */
+.theme-switcher {
+    margin-left: 1rem;
+}
+
+.theme-switcher .dropdown-toggle {
+    background: rgba(255, 255, 255, 0.1);
+    border: none;
+    border-radius: 50%;
+    width: 36px;
+    height: 36px;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    color: white;
+    transition: all 0.2s;
+}
+
+.theme-switcher .dropdown-toggle:hover {
+    background: rgba(255, 255, 255, 0.2);
+}
+
+.theme-option {
+    display: flex;
+    align-items: center;
+    padding: 0.5rem 1rem;
+    cursor: pointer;
+    transition: background-color 0.2s;
+}
+
+.theme-option:hover {
+    background-color: rgba(0, 0, 0, 0.05);
+}
+
+.theme-preview {
+    width: 20px;
+    height: 20px;
+    border-radius: 4px;
+    margin-right: 10px;
+    border: 1px solid rgba(0, 0, 0, 0.1);
+}
+
+/* Responsive adjustments */
+@media (max-width: 768px) {
+    .menu-container {
+        flex-direction: column;
+        padding: 0.5rem;
+    }
+    
+    .menu-left, .menu-right {
+        width: 100%;
+        justify-content: space-between;
+        padding: 0.25rem 0;
+    }
+}