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

:root {
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --secondary-color: #10b981;
    --warning-color: #f59e0b;
    --danger-color: #ef4444;
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-card: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    --border-color: #475569;
    --shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.3);
    --gradient: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

/* Header Styles */
.header {
    text-align: center;
    margin-bottom: 40px;
    padding: 30px 0;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
    margin-bottom: 10px;
}

.logo i {
    font-size: 2.5rem;
    color: var(--primary-color);
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.header h1 {
    font-size: 2.5rem;
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-weight: 700;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 1.1rem;
    margin-top: 10px;
}

/* Menu Styles */
.menu-container {
    margin-bottom: 40px;
}

.menu-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 25px;
    margin-bottom: 30px;
}

.menu-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 15px;
    padding: 30px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.menu-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(99, 102, 241, 0.1), transparent);
    transition: left 0.5s ease;
}

.menu-card:hover::before {
    left: 100%;
}

.menu-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow);
    border-color: var(--primary-color);
}

.card-icon {
    margin-bottom: 20px;
}

.card-icon i {
    font-size: 3rem;
    color: var(--primary-color);
}

.menu-card h3 {
    font-size: 1.5rem;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.menu-card p {
    color: var(--text-secondary);
    font-size: 1rem;
}

/* Section Styles */
.section {
    background: var(--bg-secondary);
    border-radius: 15px;
    padding: 30px;
    border: 1px solid var(--border-color);
}

.section-header {
    display: flex;
    align-items: center;
    gap: 20px;
    margin-bottom: 30px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border-color);
}

.back-btn {
    background: var(--bg-card);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    padding: 10px 15px;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 8px;
}

.back-btn:hover {
    background: var(--primary-color);
    border-color: var(--primary-color);
}

.section h2 {
    font-size: 1.8rem;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 10px;
}

.section h2 i {
    color: var(--primary-color);
}

/* Method Selector */
.method-selector {
    display: flex;
    gap: 10px;
    margin-bottom: 30px;
    background: var(--bg-card);
    padding: 5px;
    border-radius: 10px;
    border: 1px solid var(--border-color);
}

.method-btn {
    flex: 1;
    padding: 12px 20px;
    background: transparent;
    color: var(--text-secondary);
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 500;
}

.method-btn.active {
    background: var(--primary-color);
    color: white;
}

.method-btn:not(.active):hover {
    background: var(--bg-secondary);
    color: var(--text-primary);
}

/* Form Styles */
.form-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.input-group label {
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.9rem;
}

.input-group input,
.input-group select {
    padding: 12px 15px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-primary);
    font-size: 1rem;
    transition: all 0.3s ease;
}

.input-group input:focus,
.input-group select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.input-group input::placeholder {
    color: var(--text-muted);
}

/* Subjects Container */
.subjects-container {
    margin-bottom: 30px;
}

.subjects-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

.subjects-header h3 {
    color: var(--text-primary);
    font-size: 1.3rem;
}

.add-btn {
    background: var(--secondary-color);
    color: white;
    border: none;
    padding: 10px 15px;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 500;
}

.add-btn:hover {
    background: #059669;
    transform: translateY(-2px);
}

.subject-item {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr auto;
    gap: 15px;
    align-items: end;
    background: var(--bg-card);
    padding: 20px;
    border-radius: 10px;
    border: 1px solid var(--border-color);
    margin-bottom: 15px;
}

.remove-subject-btn {
    background: var(--danger-color);
    color: white;
    border: none;
    padding: 12px;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.remove-subject-btn:hover {
    background: #dc2626;
    transform: scale(1.05);
}

/* Action Buttons */
.action-buttons {
    display: flex;
    gap: 15px;
    justify-content: center;
    margin-bottom: 30px;
}

.calculate-btn {
    background: var(--gradient);
    color: white;
    border: none;
    padding: 15px 30px;
    border-radius: 10px;
    cursor: pointer;
    font-size: 1.1rem;
    font-weight: 600;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 10px;
    min-width: 160px;
    justify-content: center;
}

.calculate-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.clear-btn {
    background: transparent;
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
    padding: 15px 30px;
    border-radius: 10px;
    cursor: pointer;
    font-size: 1.1rem;
    font-weight: 600;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 10px;
    min-width: 160px;
    justify-content: center;
}

.clear-btn:hover {
    background: var(--danger-color);
    border-color: var(--danger-color);
    color: white;
    transform: translateY(-2px);
}

/* Result Container */
.result-container {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    padding: 25px;
    margin-top: 20px;
}

.result-container h3 {
    color: var(--text-primary);
    margin-bottom: 15px;
    font-size: 1.3rem;
    display: flex;
    align-items: center;
    gap: 10px;
}

.result-container h3 i {
    color: var(--secondary-color);
}

.result-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 0;
    border-bottom: 1px solid var(--border-color);
}

.result-item:last-child {
    border-bottom: none;
}

.result-label {
    color: var(--text-secondary);
    font-weight: 500;
}

.result-value {
    color: var(--text-primary);
    font-weight: 600;
    font-size: 1.1rem;
}

.result-highlight {
    color: var(--secondary-color);
}

.result-warning {
    color: var(--warning-color);
}

.result-error {
    color: var(--danger-color);
}

/* Suggestions */
.suggestions {
    margin-top: 20px;
    padding: 20px;
    background: rgba(99, 102, 241, 0.1);
    border: 1px solid var(--primary-color);
    border-radius: 10px;
}

.suggestions h4 {
    color: var(--primary-color);
    margin-bottom: 15px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.suggestion-btn {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 12px 20px;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 500;
}

.suggestion-btn:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
}

/* Table Styles */
.results-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 20px;
    background: var(--bg-card);
    border-radius: 10px;
    overflow: hidden;
    border: 1px solid var(--border-color);
}

.results-table th {
    background: var(--primary-color);
    color: white;
    padding: 15px;
    text-align: left;
    font-weight: 600;
}

.results-table td {
    padding: 12px 15px;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-primary);
}

.results-table tr:hover {
    background: rgba(99, 102, 241, 0.1);
}

.results-table .gpa-cell {
    font-weight: 600;
    color: var(--secondary-color);
}

.table-container {
    max-height: 600px;
    overflow-y: auto;
    border-radius: 10px;
}

.table-stats {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
    padding: 15px;
    background: rgba(16, 185, 129, 0.1);
    border-radius: 8px;
    border: 1px solid var(--secondary-color);
}

.table-stats span {
    color: var(--secondary-color);
    font-weight: 600;
}

/* Utility Classes */
.hidden {
    display: none !important;
}

.text-center {
    text-align: center;
}

.mt-20 {
    margin-top: 20px;
}

.mb-20 {
    margin-bottom: 20px;
}

/* Loading Animation */
.loading {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 40px;
}

.spinner {
    width: 40px;
    height: 40px;
    border: 4px solid var(--border-color);
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% {
        transform: rotate(0deg);
    }

    100% {
        transform: rotate(360deg);
    }
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 15px;
    }

    .header h1 {
        font-size: 2rem;
    }

    .menu-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }

    .form-grid {
        grid-template-columns: 1fr;
        gap: 15px;
    }

    .subject-item {
        grid-template-columns: 1fr;
        gap: 10px;
    }

    .action-buttons {
        flex-direction: column;
        align-items: center;
    }

    .calculate-btn,
    .clear-btn {
        width: 100%;
        max-width: 300px;
    }

    .section-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 15px;
    }

    .method-selector {
        flex-direction: column;
    }

    .results-table {
        font-size: 0.9rem;
    }

    .results-table th,
    .results-table td {
        padding: 10px 8px;
    }
}

@media (max-width: 480px) {
    .logo {
        flex-direction: column;
        gap: 10px;
    }

    .logo i {
        font-size: 2rem;
    }

    .header h1 {
        font-size: 1.8rem;
    }

    .menu-card {
        padding: 20px;
    }

    .card-icon i {
        font-size: 2.5rem;
    }

    .section {
        padding: 20px;
    }
}

/* Scrollbar Styling */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--primary-color);
}

/* Footer Styles */
.footer {
    text-align: center;
    padding: 30px 0;
    margin-top: 50px;
    border-top: 1px solid var(--border-color);
    background: var(--bg-secondary);
}

.footer p {
    color: var(--text-muted);
    font-size: 0.9rem;
    font-weight: 400;
}