feat: Implement login functionality with captcha verification and associated UI.

index.css

@@ -311,4 +311,107 @@ footer {
     color: var(--text-muted);
 }
 
+/* Login Overlay Styles */
+.login-overlay {
+    position: fixed;
+    top: 0;
+    left: 0;
+    width: 100%;
+    height: 100%;
+    background: transparent;
+    display: flex;
+    justify-content: center;
+    align-items: center;
+    z-index: 1000;
+    backdrop-filter: blur(12px);
+    -webkit-backdrop-filter: blur(12px);
+    transition: opacity 0.5s ease;
+}
+
+.login-card {
+    background: var(--card-bg);
+    border: 1px solid rgba(255, 255, 255, 0.4);
+    border-radius: 24px;
+    padding: 32px;
+    width: 90%;
+    max-width: 400px;
+    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.3);
+    animation: slideUp 0.6s cubic-bezier(0.16, 1, 0.3, 1) forwards;
+}
+
+.login-header {
+    text-align: center;
+    margin-bottom: 24px;
+}
+
+.login-header p {
+    color: var(--text-muted);
+    font-size: 0.9rem;
+}
+
+.full-width {
+    width: 100%;
+}
+
+.captcha-container {
+    display: flex;
+    align-items: center;
+    gap: 12px;
+    margin-bottom: 8px;
+    background: rgba(255, 255, 255, 0.5);
+    padding: 8px;
+    border-radius: 12px;
+    border: 1px solid var(--border);
+}
+
+#captchaCanvas {
+    background: #fff;
+    border-radius: 8px;
+    flex-grow: 1;
+}
+
+.icon-btn {
+    background: #f3f4f6;
+    color: var(--text);
+    padding: 8px;
+    border-radius: 8px;
+    transition: background 0.2s;
+}
+
+.icon-btn:hover {
+    background: #e5e7eb;
+}
+
+.error-message {
+    background: rgba(239, 68, 68, 0.1);
+    color: var(--danger);
+    padding: 10px;
+    border-radius: 8px;
+    font-size: 0.85rem;
+    margin-bottom: 16px;
+    text-align: center;
+    border: 1px solid rgba(239, 68, 68, 0.2);
+    animation: shake 0.4s ease-in-out;
+}
+
+@keyframes shake {
+
+    0%,
+    100% {
+        transform: translateX(0);
+    }
+
+    25% {
+        transform: translateX(-5px);
+    }
+
+    50% {
+        transform: translateX(5px);
+    }
+
+    75% {
+        transform: translateX(-5px);
+    }
+}
+
 /* Base CSS End */