diff --git a/src/components/PRGradingScreen/PRGradingScreen.jsx b/src/components/PRGradingScreen/PRGradingScreen.jsx
index afd6d22b50..cab67fae21 100644
--- a/src/components/PRGradingScreen/PRGradingScreen.jsx
+++ b/src/components/PRGradingScreen/PRGradingScreen.jsx
@@ -4,6 +4,8 @@ import { useSelector } from 'react-redux';
 import { v4 as uuidv4 } from 'uuid';
 import styles from './PRGradingScreen.module.css';
 
+const normalizePrNumbers = prNumbers => (prNumbers || '').replace(/\s+/g, '');
+
 const PRGradingScreen = ({ teamData, reviewers }) => {
   const darkMode = useSelector(state => state.theme.darkMode);
 
@@ -55,6 +57,17 @@ const PRGradingScreen = ({ teamData, reviewers }) => {
       return;
     }
 
+    const reviewer = reviewerData.find(r => r.id === reviewerId);
+    const existingPRs = reviewer?.gradedPrs ?? [];
+    const normalizedNew = normalizePrNumbers(inputValue.trim());
+    const isDuplicate = existingPRs.some(
+      pr => pr?.prNumbers && normalizePrNumbers(pr.prNumbers) === normalizedNew,
+    );
+    if (isDuplicate) {
+      setInputError(`PR number "${inputValue.trim()}" already exists for this reviewer`);
+      return;
+    }
+
     const newPREntry = {
       id: uuidv4(),
       prNumbers: inputValue.trim(),
@@ -232,11 +245,26 @@ const PRGradingScreen = ({ teamData, reviewers }) => {
                             <input
                               type="text"
                               value={inputValue}
-                              onChange={e => setInputValue(e.target.value)}
-                              className={styles['pr-grading-screen-pr-number-input']}
+                              onChange={e => {
+                                setInputValue(e.target.value);
+                                if (inputError) setInputError('');
+                              }}
+                              className={`${styles['pr-grading-screen-pr-number-input']} ${
+                                inputError ? styles['pr-grading-screen-input-error'] : ''
+                              } ${darkMode ? styles['dark-mode'] : ''}`}
                               placeholder="1070 or 1070 + 1256"
                             />
 
+                            {inputError && (
+                              <p
+                                className={`${styles['pr-grading-screen-error-message']} ${
+                                  darkMode ? styles['dark-mode'] : ''
+                                }`}
+                              >
+                                {inputError}
+                              </p>
+                            )}
+
                             <Button
                               variant="primary"
                               size="sm"
diff --git a/src/components/PRGradingScreen/PRGradingScreen.module.css b/src/components/PRGradingScreen/PRGradingScreen.module.css
index cbef93db31..f0dfcb0cc4 100644
--- a/src/components/PRGradingScreen/PRGradingScreen.module.css
+++ b/src/components/PRGradingScreen/PRGradingScreen.module.css
@@ -11,7 +11,7 @@
 
 .pr-grading-screen-card {
   border: none;
-  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
+  box-shadow: 0 4px 6px rgb(0 0 0 / 10%);
   border-radius: 8px;
   width: 100%;
   margin: 0 auto;
@@ -24,7 +24,7 @@
 }
 
 .pr-grading-screen-header {
-  background-color: #ffffff;
+  background-color: #fff;
   border-bottom: 1px solid #e9ecef;
   padding: 20px;
 }
@@ -85,10 +85,10 @@
 
 /* Table Styles */
 .pr-grading-screen-table-container {
-  margin: 20px auto 0 auto;
+  margin: 20px auto 0;
   border-radius: 8px;
   overflow: hidden;
-  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
+  box-shadow: 0 1px 3px rgb(0 0 0 / 10%);
   width: 100%;
   max-width: 100%;
 }
@@ -100,6 +100,49 @@
   table-layout: fixed;
 }
 
+/* Table Body - must come before grading-table for specificity */
+.pr-grading-screen-table tbody tr {
+  border-bottom: 1px solid #dee2e6;
+}
+
+.pr-grading-screen-table tbody tr:hover {
+  background-color: #f8f9fa;
+}
+
+/* Grading table (modal) */
+.pr-grading-screen-grading-table {
+  width: 100%;
+  border-collapse: collapse;
+  margin-bottom: 20px;
+}
+
+.pr-grading-screen-grading-table th {
+  background-color: #f8f9fa;
+  border: 1px solid #dee2e6;
+  padding: 12px 8px;
+  text-align: center;
+  font-weight: 600;
+  color: #495057;
+  font-size: 0.9rem;
+}
+
+.pr-grading-screen-grading-table td {
+  border: 1px solid #dee2e6;
+  padding: 12px 8px;
+  text-align: center;
+  vertical-align: middle;
+}
+
+.pr-grading-screen-grading-table tbody tr:hover {
+  background-color: #f8f9fa;
+}
+
+.pr-grading-screen-table tbody td {
+  padding: 16px 12px;
+  vertical-align: middle; /* Changed from top to middle for better alignment */
+  text-align: center;
+}
+
 /* Table Header */
 .pr-grading-screen-table thead th {
   background-color: #f8f9fa;
@@ -133,21 +176,6 @@
   text-align: center;
 }
 
-/* Table Body */
-.pr-grading-screen-table tbody tr {
-  border-bottom: 1px solid #dee2e6;
-}
-
-.pr-grading-screen-table tbody tr:hover {
-  background-color: #f8f9fa;
-}
-
-.pr-grading-screen-table tbody td {
-  padding: 16px 12px;
-  vertical-align: middle; /* Changed from top to middle for better alignment */
-  text-align: center;
-}
-
 /* Column 1: Reviewer Name */
 .pr-grading-screen-td-name {
   width: 24%;
@@ -173,12 +201,13 @@
 
 .pr-grading-screen-reviewer-role {
   font-size: 0.8rem;
-  /* color: #6c757d; commenting this line to remove duplicate selector issue present in later section of this page*/
+
+  /* color: #6c757d; commenting this line to remove duplicate selector issue present in later section of this page */
   color: #b0b8c4; 
   line-height: 1.3;
   text-align: center;
   max-width: 180px;
-  word-wrap: break-word;
+  overflow-wrap: break-word;
 }
 
 /* Column 2: PR reviewed */
@@ -200,7 +229,7 @@
   font-size: 1rem;
   font-weight: 500;
   color: #333;
-  background-color: #ffffff;
+  background-color: #fff;
   margin: 0 auto;
   display: block;
 }
@@ -208,7 +237,7 @@
 .pr-grading-screen-pr-input:focus {
   outline: none;
   border-color: #80bdff;
-  box-shadow: 0 0 0 2px rgba(0, 123, 255, 0.25);
+  box-shadow: 0 0 0 2px rgb(0 123 255 / 25%);
 }
 
 .pr-grading-screen-pr-input:hover {
@@ -276,7 +305,7 @@
 
 .pr-grading-screen-pr-clickable:hover {
   transform: translateY(-1px);
-  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
+  box-shadow: 0 2px 4px rgb(0 0 0 / 10%);
 }
 
 .pr-grading-screen-grade {
@@ -356,14 +385,14 @@
   font-size: 0.9rem;
   font-weight: 500;
   color: #495057;
-  background-color: #ffffff;
+  background-color: #fff;
   min-width: 150px;
 }
 
 .pr-grading-screen-pr-number-input:focus {
   outline: none;
   border-color: #80bdff;
-  box-shadow: 0 0 0 2px rgba(0, 123, 255, 0.25);
+  box-shadow: 0 0 0 2px rgb(0 123 255 / 25%);
 }
 
 .pr-grading-screen-pr-number-input.pr-grading-screen-pair-input {
@@ -384,7 +413,7 @@
 }
 
 .pr-grading-screen-error-message {
-  /* color: #dc3545; commenting this line according to recent fix inorder to remove duplicate selector*/
+  /* color: #dc3545; commenting this line according to recent fix inorder to remove duplicate selector */
   color: #f8d7da;
   font-size: 0.75rem;
   margin-top: 4px;
@@ -403,11 +432,8 @@
 /* Grading Modal Styles */
 .pr-grading-screen-modal-overlay {
   position: fixed;
-  top: 0;
-  left: 0;
-  right: 0;
-  bottom: 0;
-  background-color: rgba(0, 0, 0, 0.5);
+  inset: 0;
+  background-color: rgb(0 0 0 / 50%);
   display: flex;
   align-items: center;
   justify-content: center;
@@ -415,9 +441,9 @@
 }
 
 .pr-grading-screen-modal {
-  background-color: #ffffff;
+  background-color: #fff;
   border-radius: 8px;
-  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
+  box-shadow: 0 10px 25px rgb(0 0 0 / 20%);
   max-width: 800px;
   width: 90%;
   max-height: 80vh;
@@ -468,34 +494,6 @@
   max-height: calc(80vh - 120px);
 }
 
-/* Grading Table Styles */
-.pr-grading-screen-grading-table {
-  width: 100%;
-  border-collapse: collapse;
-  margin-bottom: 20px;
-}
-
-.pr-grading-screen-grading-table th {
-  background-color: #f8f9fa;
-  border: 1px solid #dee2e6;
-  padding: 12px 8px;
-  text-align: center;
-  font-weight: 600;
-  color: #495057;
-  font-size: 0.9rem;
-}
-
-.pr-grading-screen-grading-table td {
-  border: 1px solid #dee2e6;
-  padding: 12px 8px;
-  text-align: center;
-  vertical-align: middle;
-}
-
-.pr-grading-screen-grading-table tbody tr:hover {
-  background-color: #f8f9fa;
-}
-
 .pr-grading-screen-modal-pr-number {
   text-align: left !important;
   padding-left: 16px !important;
@@ -527,7 +525,7 @@
 
 
 /* Responsive adjustments */
-@media (max-width: 768px) {
+@media (width <= 768px) {
   .pr-grading-screen-title {
     font-size: 1.5rem;
   }
@@ -643,7 +641,7 @@
 
 .pr-grading-screen-card.dark-mode {
   background-color: #1b2a41;
-  box-shadow: 0 4px 6px rgba(255, 255, 255, 0.1);
+  box-shadow: 0 4px 6px rgb(255 255 255 / 10%);
 }
 
 .pr-grading-screen-header.dark-mode {
@@ -652,7 +650,7 @@
 }
 
 .pr-grading-screen-title.dark-mode {
-  color: #ffffff;
+  color: #fff;
 }
 
 .pr-grading-screen-team-info-badge.dark-mode {
@@ -667,7 +665,7 @@
 .pr-grading-screen-done-button.dark-mode {
   background-color: #4a5a77;
   border-color: #5a6b88;
-  color: #ffffff;
+  color: #fff;
 }
 
 .pr-grading-screen-done-button.dark-mode:hover {
@@ -681,46 +679,61 @@
 
 .card-body.dark-mode {
   background-color: #1b2a41;
-  color: #ffffff;
+  color: #fff;
 }
 
 /* Table */
 .pr-grading-screen-table-container.dark-mode {
-  box-shadow: 0 1px 3px rgba(255, 255, 255, 0.1);
+  box-shadow: 0 1px 3px rgb(255 255 255 / 10%);
 }
 
 .pr-grading-screen-table.dark-mode {
   background-color: #1b2a41;
-  color: #ffffff;
+  color: #fff;
 }
 
-.pr-grading-screen-table.dark-mode thead th {
+.pr-grading-screen-table.dark-mode tbody tr {
+  border-bottom: 1px solid #4a5a77;
+}
+
+.pr-grading-screen-grading-table.dark-mode th {
   background-color: #2d4059;
-  border-bottom: 2px solid #4a5a77;
-  color: #ffffff;
+  border-bottom: 1px solid #4a5a77;
+  color: #fff;
 }
 
-.pr-grading-screen-table.dark-mode tbody tr {
+.pr-grading-screen-grading-table.dark-mode td {
   border-bottom: 1px solid #4a5a77;
+  color: #fff;
+}
+
+.pr-grading-screen-grading-table.dark-mode tr:hover {
+  background-color: #2d4059;
 }
 
 .pr-grading-screen-table.dark-mode tbody tr:hover {
   background-color: #2d4059;
 }
 
+.pr-grading-screen-table.dark-mode thead th {
+  background-color: #2d4059;
+  border-bottom: 2px solid #4a5a77;
+  color: #fff;
+}
+
 .pr-grading-screen-table-row.dark-mode td {
-  color: #ffffff;
+  color: #fff;
 }
 
 .pr-grading-screen-table.dark-mode .pr-grading-screen-pr-input {
   background-color: #2d4059;
   border-color: #5a6b88;
-  color: #ffffff;
+  color: #fff;
 }
 
 .pr-grading-screen-table.dark-mode .pr-grading-screen-pr-input:focus {
   border-color: #e8a71c;
-  box-shadow: 0 0 0 2px rgba(232, 167, 28, 0.25);
+  box-shadow: 0 0 0 2px rgb(232 167 28 / 25%);
 }
 
 .pr-grading-screen-table.dark-mode .pr-grading-screen-pr-input:hover {
@@ -730,7 +743,7 @@
 /* PR Number Pills */
 .pr-grading-screen-table.dark-mode .pr-grading-screen-pr-number {
   background-color: #2d4059;
-  color: #ffffff;
+  color: #fff;
   border-color: #5a6b88;
 }
 
@@ -743,7 +756,7 @@
 .pr-grading-screen-table.dark-mode .pr-grading-screen-pr-clickable:hover {
   background-color: #3a506b;
   transform: translateY(-1px);
-  box-shadow: 0 2px 4px rgba(255, 255, 255, 0.1);
+  box-shadow: 0 2px 4px rgb(255 255 255 / 10%);
 }
 
 /* Buttons */
@@ -759,29 +772,29 @@
 
 /* Modal */
 .pr-grading-screen-modal-overlay.dark-mode {
-  background-color: rgba(27, 42, 65, 0.8);
+  background-color: rgb(27 42 65 / 80%);
 }
 
 .pr-grading-screen-modal.dark-mode {
   background-color: #1b2a41;
   border: 1px solid #4a5a77;
-  box-shadow: 0 4px 6px rgba(255, 255, 255, 0.1);
+  box-shadow: 0 4px 6px rgb(255 255 255 / 10%);
 }
 
 .pr-grading-screen-modal-header.dark-mode {
   background-color: #2d4059;
   border-bottom: 1px solid #4a5a77;
-  color: #ffffff;
+  color: #fff;
 }
 
 .pr-grading-screen-modal-header.dark-mode h3 {
-  color: #ffffff;
+  color: #fff;
 }
 
 .pr-grading-screen-modal-close.dark-mode {
   background-color: transparent;
   border: none;
-  color: #ffffff;
+  color: #fff;
   font-size: 24px;
 }
 
@@ -791,45 +804,34 @@
 
 .pr-grading-screen-modal-body.dark-mode {
   background-color: #1b2a41;
-  color: #ffffff;
+  color: #fff;
 }
 
 .pr-grading-screen-grading-table.dark-mode {
   background-color: #1b2a41;
-  color: #ffffff;
-}
-
-.pr-grading-screen-grading-table.dark-mode th {
-  background-color: #2d4059;
-  border-bottom: 1px solid #4a5a77;
-  color: #ffffff;
-}
-
-.pr-grading-screen-grading-table.dark-mode td {
-  border-bottom: 1px solid #4a5a77;
-  color: #ffffff;
-}
-
-.pr-grading-screen-grading-table.dark-mode tr:hover {
-  background-color: #2d4059;
+  color: #fff;
 }
 
 /* Input and Form Elements */
 .pr-grading-screen-pr-number-input.dark-mode {
   background-color: #2d4059;
   border-color: #5a6b88;
-  color: #ffffff;
+  color: #fff;
 }
 
 .pr-grading-screen-pr-number-input.dark-mode:focus {
   border-color: #e8a71c;
-  box-shadow: 0 0 0 2px rgba(232, 167, 28, 0.25);
+  box-shadow: 0 0 0 2px rgb(232 167 28 / 25%);
 }
 
 .pr-grading-screen-input-error.dark-mode {
   border-color: #dc3545;
 }
 
+.pr-grading-screen-error-message.dark-mode {
+  color: #f87171;
+}
+
 /* .pr-grading-screen-pair-message {
   color: #a7f3d0;
 } */
@@ -838,7 +840,7 @@
 .pr-grading-screen-done-btn.dark-mode {
   background-color: #007bff;
   border-color: #007bff;
-  color: #ffffff;
+  color: #fff;
 }
 
 .pr-grading-screen-done-btn.dark-mode:hover {
@@ -869,7 +871,7 @@
 .btn-secondary.dark-mode {
   background-color: #6c757d;
   border-color: #6c757d;
-  color: #ffffff;
+  color: #fff;
 }
 
 .btn-secondary.dark-mode:hover {