:root {
     --primary: #4361ee;
     --primary-dark: #3a56d4;
     --secondary: #7209b7;
     --success: #2ecc71;
     --warning: #f39c12;
     --danger: #e74c3c;
     --dark: #2d3436;
     --light: #f8f9fa;
     --gray: #6c757d;
     --border-radius: 12px;
     --box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
     --transition: all 0.3s ease;
 }

 * {
     margin: 0;
     padding: 0;
     box-sizing: border-box;
 }

 body {
     font-family: 'Inter', sans-serif;
     /* background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%); */
     /* background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); */
     min-height: 100vh;
     display: flex;
     justify-content: center;
     align-items: center;
     padding: 20px;
     color: var(--dark);
     line-height: 1.6;
     background-image: url("./university.jpg");
     background-repeat: no-repeat;
     background-position: center center;
     background-size: cover;
 }

 .container {
     width: 100%;
     max-width: 1000px;
     background: white;
     border-radius: var(--border-radius);
     box-shadow: var(--box-shadow);
     overflow: hidden;
     display: grid;
     grid-template-columns: 1fr 1.2fr;
     min-height: 650px;
 }

 /* Left Panel - Input Section */
 .input-section {
     background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
     padding: 40px 30px;
     color: white;
     display: flex;
     flex-direction: column;
 }

 .input-section h1 {
     font-size: 2.2rem;
     margin-bottom: 10px;
     font-weight: 700;
     display: flex;
     align-items: center;
     gap: 15px;
 }

 .input-section h1 i {
     background: rgba(255, 255, 255, 0.2);
     padding: 12px;
     border-radius: 50%;
 }

 .subtitle {
     font-size: 1rem;
     opacity: 0.9;
     margin-bottom: 40px;
 }

 .input-group {
     margin-bottom: 25px;
 }

 .input-group label {
     display: block;
     margin-bottom: 8px;
     font-weight: 500;
     font-size: 1.1rem;
 }

 .input-group input {
     width: 100%;
     padding: 16px 20px;
     border: none;
     border-radius: var(--border-radius);
     background: rgba(255, 255, 255, 0.15);
     color: white;
     font-size: 1.1rem;
     font-weight: 500;
     border: 2px solid rgba(255, 255, 255, 0.1);
     transition: var(--transition);
 }

 .input-group input:focus {
     outline: none;
     border-color: rgba(255, 255, 255, 0.5);
     background: rgba(255, 255, 255, 0.2);
 }

 .input-group input::placeholder {
     color: rgba(255, 255, 255, 0.6);
 }

 .marks-range {
     display: flex;
     justify-content: space-between;
     font-size: 0.85rem;
     opacity: 0.8;
     margin-top: 5px;
 }

 .calculate-btn {
     background: white;
     color: var(--primary);
     border: none;
     padding: 18px;
     border-radius: var(--border-radius);
     font-size: 1.2rem;
     font-weight: 600;
     cursor: pointer;
     display: flex;
     align-items: center;
     justify-content: center;
     gap: 12px;
     transition: var(--transition);
     margin-top: 10px;
     box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
 }

 .calculate-btn:hover {
     transform: translateY(-3px);
     box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
 }


 /* Hide up/down arrows in input fields for all browsers */
 input[type="number"]::-webkit-inner-spin-button,
 input[type="number"]::-webkit-outer-spin-button {
     -webkit-appearance: none;
     margin: 0;
 }

 /* Firefox */
 input[type="number"] {
     appearance: textfield;
 }


 /* Right Panel - Results Section */
 .results-section {
     padding: 40px 35px;
     display: flex;
     flex-direction: column;
 }

 .results-section h2 {
     color: var(--primary);
     font-size: 1.8rem;
     margin-bottom: 30px;
     display: flex;
     align-items: center;
     gap: 12px;
 }

 .grade-display {
     background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
     border-radius: var(--border-radius);
     padding: 30px;
     text-align: center;
     margin-bottom: 30px;
     border: 2px dashed #dee2e6;
 }

 .percentage {
     font-size: 3.5rem;
     font-weight: 700;
     color: var(--primary);
     margin-bottom: 10px;
 }

 .grade-text {
     font-size: 1.5rem;
     font-weight: 600;
     color: var(--dark);
 }

 .grade-details {
     display: grid;
     grid-template-columns: repeat(2, 1fr);
     gap: 20px;
     margin-bottom: 30px;
 }

 .detail-card {
     background: #f8f9fa;
     border-radius: var(--border-radius);
     padding: 20px;
     border-left: 4px solid var(--primary);
     transition: var(--transition);
 }

 .detail-card:hover {
     transform: translateY(-5px);
     box-shadow: 0 8px 20px rgba(0, 0, 0, 0.08);
 }

 .detail-card h3 {
     font-size: 0.9rem;
     color: var(--gray);
     margin-bottom: 8px;
     text-transform: uppercase;
     letter-spacing: 0.5px;
 }

 .detail-card p {
     font-size: 1.4rem;
     font-weight: 600;
     color: var(--dark);
 }

 .grade-scale {
     margin-top: auto;
 }

 .grade-scale h3 {
     font-size: 1.1rem;
     margin-bottom: 15px;
     color: var(--dark);
     display: flex;
     align-items: center;
     gap: 10px;
 }

 .scale-grid {
     display: grid;
     grid-template-columns: repeat(5, 1fr);
     gap: 10px;
 }

 .scale-item {
     padding: 12px;
     border-radius: 8px;
     text-align: center;
     font-weight: 600;
     color: white;
 }

 .scale-A {
     background: var(--success);
 }

 .scale-B {
     background: #3498db;
 }

 .scale-C {
     background: var(--warning);
 }

 .scale-D {
     background: #e67e22;
 }

 .scale-F {
     background: var(--danger);
 }

 /* Grade Colors */
 .grade-A {
     color: var(--success);
 }

 .grade-B {
     color: #3498db;
 }

 .grade-C {
     color: var(--warning);
 }

 .grade-D {
     color: #e67e22;
 }

 .grade-F {
     color: var(--danger);
 }

 /* Responsive */
 @media (max-width: 900px) {
     .container {
         grid-template-columns: 1fr;
         max-width: 500px;
     }

     .input-section {
         padding: 30px 25px;
     }
 }

 @media (max-width: 480px) {
     .grade-details {
         grid-template-columns: 1fr;
     }

     .scale-grid {
         grid-template-columns: repeat(3, 1fr);
     }

     .percentage {
         font-size: 2.8rem;
     }
 }

 /* Animation */
 @keyframes fadeIn {
     from {
         opacity: 0;
         transform: translateY(20px);
     }

     to {
         opacity: 1;
         transform: translateY(0);
     }
 }

 .fade-in {
     animation: fadeIn 0.5s ease forwards;
 }