add animation for box-shadow

css/main.css

@@ -15,7 +15,12 @@ body {
     position: relative;
 }
 
-h1, h2, h3, h4, h5, h6 {
+h1,
+h2,
+h3,
+h4,
+h5,
+h6 {
     font-weight: 600;
     color: var(--text-color);
 }
@@ -46,7 +51,11 @@ img {
     border-radius: var(--border-radius);
     border-top: 1px solid var(--glass-border);
     border-bottom: 1px solid var(--glass-border);
-    box-shadow: var(--box-shadow), var(--inset-shadow);
+    /* base shadows: outer shadow from variables + subtle inset
+         an extra animated outer shadow is layered to give a natural "alive" feel */
+    box-shadow: 0 8px 36px 0 var(--glass-shadow), var(--inset-shadow);
+    will-change: box-shadow;
+    animation: glass-shadow 8s ease-in-out infinite !important;
 }
 
 .main-container {
@@ -67,12 +76,36 @@ img {
         opacity: 0;
         transform: translateY(30px);
     }
+
     to {
         opacity: 1;
         transform: translateY(0);
     }
 }
 
+/* subtle, natural moving/pulsing shadow for .glass */
+@keyframes glass-shadow {
+    0% {
+        box-shadow: 0 6px 24px -2px var(--glass-shadow), 0 18px 48px -12px var(--dark-shadow-15), inset 0 1px 0 rgba(255, 255, 255, 0.1);
+    }
+
+    25% {
+        box-shadow: 6px 10px 38px -6px var(--tertiary-color-20), 0 22px 60px -18px var(--dark-shadow-18), inset 0 1px 0 rgba(255, 255, 255, 0.1);
+    }
+
+    50% {
+        box-shadow: 0 8px 36px 0 var(--glass-shadow), 0 28px 72px -24px var(--dark-shadow-20), inset 0 1px 0 rgba(255, 255, 255, 0.1);
+    }
+
+    75% {
+        box-shadow: -6px 10px 38px -6px var(--primary-color-16), 0 22px 60px -18px rgba(0, 0, 0, 0.12), inset 0 1px 0 rgba(255, 255, 255, 0.1);
+    }
+
+    100% {
+        box-shadow: 0 6px 24px -2px var(--glass-shadow), 0 18px 48px -12px var(--dark-shadow-15), inset 0 1px 0 rgba(255, 255, 255, 0.1);
+    }
+}
+
 .content {
     color: var(--text-color);
     background: rgba(0, 0, 0, 0.10);
@@ -97,3 +130,10 @@ img {
         font-size: 14px;
     }
 }
+
+/* Accessibility: disable animated shadows for users who prefer reduced motion */
+@media (prefers-reduced-motion: reduce) {
+    .glass {
+        animation: none !important;
+    }
+}

css/variables.css

@@ -24,4 +24,10 @@
 
     --box-shadow: 0 8px 36px 0px var(--glass-shadow);
     --inset-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.1);
+    /* semi-transparent helpers for animated shadows */
+    --primary-color-16: rgba(55, 187, 248, 0.16);
+    --tertiary-color-20: rgba(106, 50, 161, 0.2);
+    --dark-shadow-15: rgba(0,0,0,0.15);
+    --dark-shadow-18: rgba(0,0,0,0.18);
+    --dark-shadow-20: rgba(0,0,0,0.20);
 }