/* ======================= GPA CALCULATOR STYLES ======================= */

.gpa-calculator-section {
    padding: 2rem 0 4rem;
    min-height: 60vh;
}

/* ======================= CALCULATOR CARD ======================= */
.gpa-calculator-card {
    background: white;
    border-radius: var(--radius-2xl);
    box-shadow: var(--shadow-xl);
    overflow: hidden;
    transition: all var(--transition-normal);
}

.gpa-calculator-card:hover {
    box-shadow: var(--shadow-2xl);
    transform: translateY(-4px);
}

.gpa-calculator-header {
    background: linear-gradient(135deg, #8b5cf6 0%, #6d28d9 100%);
    padding: 1.5rem 2rem;
    display: flex;
    align-items: center;
    gap: 1rem;
}

.gpa-calculator-icon {
    width: 52px;
    height: 52px;
    background: rgba(255, 255, 255, 0.15);
    border-radius: var(--radius-xl);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    color: white;
}

.gpa-calculator-title {
    color: white;
    font-size: 1.25rem;
    font-weight: 700;
    margin: 0;
}

.gpa-calculator-subtitle {
    color: rgba(255, 255, 255, 0.8);
    font-size: 0.875rem;
    margin: 0.25rem 0 0;
}

.gpa-calculator-body {
    padding: 2rem;
}

/* ======================= GRADE SYSTEM SELECTOR ======================= */
.grade-system-selector {
    margin-bottom: 1.5rem;
}

.gpa-label {
    display: block;
    font-size: 0.8125rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 0.75rem;
}

.grade-system-tabs {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: 0.75rem;
}

.grade-system-tab {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 1rem;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-lg);
    background: white;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
    gap: 0.375rem;
}

.grade-system-tab:hover {
    border-color: #8b5cf6;
    background: rgba(139, 92, 246, 0.05);
}

.grade-system-tab.active {
    border-color: #8b5cf6;
    background: #8b5cf6;
    color: white;
}

.grade-system-tab i {
    font-size: 1.25rem;
}

.grade-system-tab span {
    font-size: 0.875rem;
    font-weight: 600;
}

.grade-system-tab small {
    font-size: 0.75rem;
    opacity: 0.8;
}

/* ======================= SEMESTER SELECTOR ======================= */
.semester-selector {
    margin-bottom: 1.5rem;
}

.calculation-type-tabs {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 0.75rem;
}

.calc-type-tab {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.875rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-lg);
    background: white;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
    font-weight: 600;
    font-size: 0.9375rem;
}

.calc-type-tab:hover {
    border-color: #8b5cf6;
    background: rgba(139, 92, 246, 0.05);
}

.calc-type-tab.active {
    border-color: #8b5cf6;
    background: #8b5cf6;
    color: white;
}

/* ======================= CUMULATIVE INPUT ======================= */
.cumulative-input-section {
    margin-bottom: 1.5rem;
    padding: 1.25rem;
    background: rgba(139, 92, 246, 0.05);
    border-radius: var(--radius-lg);
    border: 1px dashed #8b5cf6;
}

.gpa-input {
    width: 100%;
    padding: 0.75rem 1rem;
    font-size: 1rem;
    font-weight: 500;
    color: var(--text-primary);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-lg);
    background: white;
    transition: all var(--transition-fast);
}

.gpa-input:focus {
    outline: none;
    border-color: #8b5cf6;
    box-shadow: 0 0 0 4px rgba(139, 92, 246, 0.1);
}

/* ======================= COURSES SECTION ======================= */
.courses-section {
    margin-bottom: 1.5rem;
}

.courses-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.courses-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0;
}

.btn-add-course {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.625rem 1.25rem;
    background: #8b5cf6;
    color: white;
    border: none;
    border-radius: var(--radius-lg);
    font-size: 0.875rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.btn-add-course:hover {
    background: #7c3aed;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(139, 92, 246, 0.3);
}

.courses-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

/* ======================= COURSE ITEM ======================= */
.course-item {
    display: flex;
    align-items: flex-start;
    gap: 1rem;
    padding: 1.25rem;
    background: var(--bg-body);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-xl);
    transition: all var(--transition-fast);
}

.course-item:hover {
    border-color: #8b5cf6;
    background: white;
}

.course-number {
    width: 36px;
    height: 36px;
    background: linear-gradient(135deg, #8b5cf6 0%, #6d28d9 100%);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 0.875rem;
    flex-shrink: 0;
}

.course-inputs {
    flex: 1;
    display: grid;
    grid-template-columns: 1fr auto auto;
    gap: 1rem;
    align-items: end;
}

.course-input-group {
    display: flex;
    flex-direction: column;
    gap: 0.375rem;
}

.course-input-small {
    max-width: 100px;
}

.course-input-medium {
    max-width: 180px;
}

.course-label {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.3px;
}

.course-input,
.course-select {
    width: 100%;
    padding: 0.625rem 0.875rem;
    font-size: 0.9375rem;
    font-weight: 500;
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    background: white;
    transition: all var(--transition-fast);
}

.course-input:focus,
.course-select:focus {
    outline: none;
    border-color: #8b5cf6;
    box-shadow: 0 0 0 3px rgba(139, 92, 246, 0.1);
}

.btn-remove-course {
    width: 36px;
    height: 36px;
    background: transparent;
    color: var(--text-muted);
    border: 1px solid var(--border-color);
    border-radius: 50%;
    cursor: pointer;
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.btn-remove-course:hover {
    background: #fee2e2;
    border-color: #ef4444;
    color: #ef4444;
}

/* ======================= QUICK ADD SECTION ======================= */
.quick-add-section {
    margin-bottom: 1.5rem;
    padding: 1rem;
    background: var(--bg-body);
    border-radius: var(--radius-lg);
}

.quick-add-buttons {
    display: flex;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.quick-add-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.625rem 1rem;
    background: white;
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 0.8125rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.quick-add-btn:hover {
    border-color: #8b5cf6;
    color: #8b5cf6;
    background: rgba(139, 92, 246, 0.05);
}

/* ======================= GPA RESULTS ======================= */
.gpa-results {
    background: linear-gradient(135deg, #f0fdf4 0%, #dcfce7 100%);
    border: 2px solid #86efac;
    border-radius: var(--radius-xl);
    padding: 2rem;
    margin-bottom: 1.5rem;
}

.result-main {
    text-align: center;
    margin-bottom: 1.5rem;
}

.result-label {
    font-size: 0.875rem;
    font-weight: 600;
    color: #15803d;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 0.5rem;
}

.result-value {
    font-size: 4rem;
    font-weight: 800;
    color: #166534;
    line-height: 1;
    margin-bottom: 0.25rem;
}

.result-scale {
    font-size: 1rem;
    color: #22c55e;
    font-weight: 600;
}

.result-details {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
    margin-bottom: 1.5rem;
    padding: 1.25rem;
    background: white;
    border-radius: var(--radius-lg);
}

.result-detail-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.result-detail-item i {
    font-size: 1.5rem;
    color: #22c55e;
}

.result-detail-content {
    display: flex;
    flex-direction: column;
}

.result-detail-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    font-weight: 500;
}

.result-detail-value {
    font-size: 1.125rem;
    font-weight: 700;
    color: var(--text-primary);
}

.result-grade-info {
    text-align: center;
}

.grade-classification {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
}

.grade-badge {
    display: inline-block;
    padding: 0.5rem 1.5rem;
    font-size: 1.5rem;
    font-weight: 800;
    border-radius: var(--radius-lg);
    background: white;
    color: var(--text-primary);
}

.grade-badge.summa-cum-laude {
    background: linear-gradient(135deg, #fef3c7 0%, #fde68a 100%);
    color: #92400e;
    border: 2px solid #fbbf24;
}

.grade-badge.magna-cum-laude {
    background: linear-gradient(135deg, #dbeafe 0%, #bfdbfe 100%);
    color: #1e40af;
    border: 2px solid #60a5fa;
}

.grade-badge.cum-laude {
    background: linear-gradient(135deg, #e0e7ff 0%, #c7d2fe 100%);
    color: #4338ca;
    border: 2px solid #818cf8;
}

.grade-badge.honors {
    background: linear-gradient(135deg, #dcfce7 0%, #bbf7d0 100%);
    color: #166534;
    border: 2px solid #86efac;
}

.grade-badge.satisfactory {
    background: linear-gradient(135deg, #fef9c3 0%, #fef08a 100%);
    color: #854d0e;
    border: 2px solid #facc15;
}

.grade-description {
    font-size: 0.9375rem;
    color: #15803d;
    font-weight: 600;
}

/* ======================= CALCULATOR FOOTER ======================= */
.gpa-calculator-footer {
    background: var(--bg-body);
    padding: 1rem 2rem;
    border-top: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 0.75rem;
}

.footer-info {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.8125rem;
    color: var(--text-muted);
}

.btn-save-calculation {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.625rem 1.25rem;
    background: #8b5cf6;
    color: white;
    border: none;
    border-radius: var(--radius-lg);
    font-size: 0.875rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.btn-save-calculation:hover {
    background: #7c3aed;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(139, 92, 246, 0.3);
}

/* ======================= GRADE SCALE CARD ======================= */
.grade-scale-card {
    background: white;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-md);
    margin-top: 1.5rem;
    overflow: hidden;
}

.grade-scale-header {
    padding: 1rem 1.5rem;
    background: var(--bg-body);
    border-bottom: 1px solid var(--border-color);
}

.grade-scale-header h5 {
    margin: 0;
    font-size: 0.9375rem;
    font-weight: 600;
    color: var(--text-primary);
}

.grade-scale-body {
    padding: 1rem;
}

.grade-scale-table {
    width: 100%;
    border-collapse: collapse;
}

.grade-scale-table th {
    font-size: 0.8125rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    text-align: left;
    padding: 0.75rem;
    border-bottom: 2px solid var(--border-color);
}

.grade-scale-table td {
    font-size: 0.875rem;
    color: var(--text-primary);
    padding: 0.75rem;
    border-bottom: 1px solid var(--border-color);
}

.grade-scale-table tbody tr:last-child td {
    border-bottom: none;
}

/* ======================= SIDEBAR ======================= */
.tips-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.tip-item {
    display: flex;
    gap: 0.75rem;
    align-items: flex-start;
}

.tip-item i {
    font-size: 1.125rem;
    flex-shrink: 0;
    margin-top: 0.125rem;
}

.tip-item p {
    margin: 0;
    font-size: 0.875rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

.classification-list {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.classification-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 0.75rem;
    background: var(--bg-body);
    border-radius: var(--radius-md);
}

.classification-badge {
    padding: 0.375rem 0.75rem;
    font-size: 0.75rem;
    font-weight: 700;
    border-radius: var(--radius-md);
    white-space: nowrap;
}

.classification-badge.summa-cum-laude {
    background: #fef3c7;
    color: #92400e;
}

.classification-badge.magna-cum-laude {
    background: #dbeafe;
    color: #1e40af;
}

.classification-badge.cum-laude {
    background: #e0e7ff;
    color: #4338ca;
}

.classification-badge.honors {
    background: #dcfce7;
    color: #166534;
}

.classification-badge.satisfactory {
    background: #fef9c3;
    color: #854d0e;
}

.classification-info {
    display: flex;
    flex-direction: column;
}

.classification-info strong {
    font-size: 0.875rem;
    color: var(--text-primary);
}

.classification-info small {
    font-size: 0.75rem;
    color: var(--text-muted);
}

/* ======================= HISTORY ======================= */
.gpa-history {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.history-item {
    padding: 1rem;
    background: var(--bg-body);
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: all var(--transition-fast);
    border: 1px solid transparent;
}

.history-item:hover {
    background: white;
    border-color: #8b5cf6;
    transform: translateY(-2px);
}

.history-item-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.5rem;
}

.history-gpa {
    font-size: 1.5rem;
    font-weight: 800;
    color: #8b5cf6;
}

.history-scale {
    font-size: 0.75rem;
    color: var(--text-muted);
    font-weight: 500;
}

.history-item-details {
    display: flex;
    gap: 1rem;
    margin-bottom: 0.375rem;
}

.history-item-details small {
    display: flex;
    align-items: center;
    gap: 0.375rem;
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.history-item-date {
    margin-top: 0.375rem;
}

.history-item-date small {
    display: flex;
    align-items: center;
    gap: 0.375rem;
    font-size: 0.75rem;
    color: var(--text-muted);
}

/* ======================= RESPONSIVE ======================= */
@media (max-width: 991.98px) {
    .gpa-calculator-section {
        padding: 1.5rem 0 3rem;
    }

    .gpa-calculator-body {
        padding: 1.5rem;
    }

    .result-value {
        font-size: 3rem;
    }

    .result-details {
        grid-template-columns: 1fr;
        gap: 0.75rem;
    }
}

@media (max-width: 767.98px) {
    .grade-system-tabs {
        grid-template-columns: repeat(2, 1fr);
    }

    .calculation-type-tabs {
        grid-template-columns: 1fr;
    }

    .course-inputs {
        grid-template-columns: 1fr;
    }

    .course-input-small,
    .course-input-medium {
        max-width: 100%;
    }

    .result-details {
        padding: 1rem;
    }

    .result-detail-item {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
    }

    .quick-add-buttons {
        flex-direction: column;
    }

    .quick-add-btn {
        width: 100%;
        justify-content: center;
    }

    .gpa-calculator-footer {
        flex-direction: column;
        align-items: stretch;
    }

    .btn-save-calculation {
        width: 100%;
        justify-content: center;
    }
}

@media (max-width: 575.98px) {
    .gpa-calculator-header {
        padding: 1.25rem;
    }

    .gpa-calculator-body {
        padding: 1.25rem;
    }

    .gpa-calculator-icon {
        width: 44px;
        height: 44px;
        font-size: 1.25rem;
    }

    .gpa-calculator-title {
        font-size: 1.125rem;
    }

    .grade-system-tabs {
        grid-template-columns: 1fr;
        gap: 0.5rem;
    }

    .grade-system-tab {
        flex-direction: row;
        justify-content: flex-start;
        padding: 0.875rem;
    }

    .course-item {
        flex-direction: column;
        gap: 0.75rem;
    }

    .course-number {
        width: 32px;
        height: 32px;
        font-size: 0.8125rem;
    }

    .btn-remove-course {
        width: 100%;
        border-radius: var(--radius-md);
    }

    .result-value {
        font-size: 2.5rem;
    }

    .result-scale {
        font-size: 0.875rem;
    }

    .cumulative-input-section {
        padding: 1rem;
    }
}

/* ======================= ANIMATIONS ======================= */
@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.course-item {
    animation: slideIn 0.3s ease-out;
}

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.05);
    }
}

.grade-badge {
    animation: pulse 2s ease-in-out infinite;
}

/* ======================= PRINT STYLES ======================= */
@media print {
    .gpa-calculator-section {
        padding: 0;
    }

    .page-header,
    .sidebar-card,
    .btn-add-course,
    .btn-remove-course,
    .quick-add-section,
    .gpa-calculator-footer,
    .grade-system-selector,
    .semester-selector {
        display: none !important;
    }

    .gpa-calculator-card {
        box-shadow: none;
        border: 1px solid #000;
    }

    .gpa-results {
        page-break-inside: avoid;
    }

    .courses-list {
        page-break-inside: avoid;
    }
}

/* ======================= ACCESSIBILITY ======================= */
.course-input:focus-visible,
.course-select:focus-visible,
.gpa-input:focus-visible {
    outline: 3px solid #8b5cf6;
    outline-offset: 2px;
}

.btn-add-course:focus-visible,
.btn-save-calculation:focus-visible,
.btn-remove-course:focus-visible {
    outline: 3px solid #8b5cf6;
    outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    .grade-system-tab,
    .calc-type-tab,
    .course-item {
        border-width: 3px;
    }

    .grade-badge {
        border-width: 3px;
    }
}

/* Reduced motion support */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }

    .course-item {
        animation: none;
    }

    .grade-badge {
        animation: none;
    }
}

/* ======================= DARK MODE SUPPORT (Optional) ======================= */
@media (prefers-color-scheme: dark) {
    .gpa-calculator-card {
        background: #1f2937;
    }

    .gpa-calculator-body {
        background: #1f2937;
    }

    .course-item {
        background: #111827;
        border-color: #374151;
    }

    .course-input,
    .course-select,
    .gpa-input {
        background: #111827;
        border-color: #374151;
        color: #f9fafb;
    }

    .grade-scale-card {
        background: #1f2937;
    }

    .grade-scale-table th,
    .grade-scale-table td {
        color: #f9fafb;
        border-color: #374151;
    }
}

/* ======================= UTILITY CLASSES ======================= */
.text-purple {
    color: #8b5cf6;
}

.bg-purple-soft {
    background: rgba(139, 92, 246, 0.1);
}

.border-purple {
    border-color: #8b5cf6;
}

/* ======================= LOADING STATE ======================= */
.loading-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(255, 255, 255, 0.9);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 10;
    border-radius: var(--radius-xl);
}

.loading-spinner {
    width: 40px;
    height: 40px;
    border: 4px solid #e5e7eb;
    border-top-color: #8b5cf6;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

/* ======================= EMPTY STATE ======================= */
.empty-state {
    text-align: center;
    padding: 3rem 1.5rem;
    color: var(--text-muted);
}

.empty-state i {
    font-size: 3rem;
    margin-bottom: 1rem;
    opacity: 0.5;
}

.empty-state h4 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.empty-state p {
    font-size: 0.875rem;
    margin: 0;
}

/* ======================= TOOLTIP ======================= */
.tooltip-wrapper {
    position: relative;
    display: inline-block;
}

.tooltip-content {
    position: absolute;
    bottom: 100%;
    left: 50%;
    transform: translateX(-50%);
    margin-bottom: 0.5rem;
    padding: 0.5rem 0.75rem;
    background: #1f2937;
    color: white;
    font-size: 0.75rem;
    border-radius: var(--radius-md);
    white-space: nowrap;
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--transition-fast);
    z-index: 100;
}

.tooltip-wrapper:hover .tooltip-content {
    opacity: 1;
}

.tooltip-content::after {
    content: '';
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%);
    border: 4px solid transparent;
    border-top-color: #1f2937;
}

/* ======================= BADGE VARIANTS ======================= */
.badge-success {
    background: #dcfce7;
    color: #166534;
    padding: 0.25rem 0.625rem;
    border-radius: var(--radius-md);
    font-size: 0.75rem;
    font-weight: 600;
}

.badge-warning {
    background: #fef9c3;
    color: #854d0e;
    padding: 0.25rem 0.625rem;
    border-radius: var(--radius-md);
    font-size: 0.75rem;
    font-weight: 600;
}

.badge-info {
    background: #dbeafe;
    color: #1e40af;
    padding: 0.25rem 0.625rem;
    border-radius: var(--radius-md);
    font-size: 0.75rem;
    font-weight: 600;
}

/* ======================= SCROLL BEHAVIOR ======================= */
.courses-list {
    max-height: 600px;
    overflow-y: auto;
    padding-right: 0.5rem;
}

.courses-list::-webkit-scrollbar {
    width: 8px;
}

.courses-list::-webkit-scrollbar-track {
    background: var(--bg-body);
    border-radius: var(--radius-md);
}

.courses-list::-webkit-scrollbar-thumb {
    background: #d1d5db;
    border-radius: var(--radius-md);
}

.courses-list::-webkit-scrollbar-thumb:hover {
    background: #9ca3af;
}

/* ======================= FOCUS STATES ======================= */
.grade-system-tab:focus,
.calc-type-tab:focus {
    outline: 2px solid #8b5cf6;
    outline-offset: 2px;
}

/* ======================= TRANSITION EFFECTS ======================= */
.course-item {
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.course-item:hover {
    transform: translateX(4px);
}

.btn-add-course:active,
.btn-save-calculation:active {
    transform: translateY(0) scale(0.98);
}

/* ======================= GRADIENT BACKGROUNDS ======================= */
.gradient-purple {
    background: linear-gradient(135deg, #8b5cf6 0%, #6d28d9 100%);
}

.gradient-green {
    background: linear-gradient(135deg, #10b981 0%, #059669 100%);
}

.gradient-blue {
    background: linear-gradient(135deg, #3b82f6 0%, #2563eb 100%);
}

/* ======================= CARD HOVER EFFECTS ======================= */
.sidebar-card {
    transition: all var(--transition-normal);
}

.sidebar-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
}

/* ======================= INPUT VALIDATION ======================= */
.course-input.invalid,
.course-select.invalid,
.gpa-input.invalid {
    border-color: #ef4444;
}

.course-input.valid,
.course-select.valid,
.gpa-input.valid {
    border-color: #22c55e;
}

.validation-message {
    font-size: 0.75rem;
    margin-top: 0.25rem;
    color: #ef4444;
}

/* ======================= SUCCESS MESSAGE ======================= */
.success-message {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1rem;
    background: #dcfce7;
    border: 1px solid #86efac;
    border-radius: var(--radius-md);
    color: #166534;
    font-size: 0.875rem;
    font-weight: 500;
    margin-bottom: 1rem;
}

.success-message i {
    font-size: 1.125rem;
}

/* ======================= ERROR MESSAGE ======================= */
.error-message {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1rem;
    background: #fee2e2;
    border: 1px solid #fca5a5;
    border-radius: var(--radius-md);
    color: #991b1b;
    font-size: 0.875rem;
    font-weight: 500;
    margin-bottom: 1rem;
}

.error-message i {
    font-size: 1.125rem;
}

/* ======================= SKELETON LOADING ======================= */
.skeleton {
    background: linear-gradient(90deg, #f3f4f6 25%, #e5e7eb 50%, #f3f4f6 75%);
    background-size: 200% 100%;
    animation: loading 1.5s ease-in-out infinite;
    border-radius: var(--radius-md);
}

@keyframes loading {
    0% {
        background-position: 200% 0;
    }
    100% {
        background-position: -200% 0;
    }
}

.skeleton-text {
    height: 1rem;
    margin-bottom: 0.5rem;
}

.skeleton-button {
    height: 2.5rem;
    width: 100%;
}

/* ======================= CUSTOM CHECKBOX/RADIO ======================= */
.custom-checkbox,
.custom-radio {
    position: relative;
    padding-left: 1.75rem;
    cursor: pointer;
    user-select: none;
}

.custom-checkbox input,
.custom-radio input {
    position: absolute;
    opacity: 0;
    cursor: pointer;
}

.checkmark {
    position: absolute;
    top: 0;
    left: 0;
    height: 1.25rem;
    width: 1.25rem;
    background-color: white;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
}

.custom-radio .checkmark {
    border-radius: 50%;
}

.custom-checkbox:hover input ~ .checkmark,
.custom-radio:hover input ~ .checkmark {
    border-color: #8b5cf6;
}

.custom-checkbox input:checked ~ .checkmark,
.custom-radio input:checked ~ .checkmark {
    background-color: #8b5cf6;
    border-color: #8b5cf6;
}

.checkmark:after {
    content: "";
    position: absolute;
    display: none;
}

.custom-checkbox input:checked ~ .checkmark:after,
.custom-radio input:checked ~ .checkmark:after {
    display: block;
}

.custom-checkbox .checkmark:after {
    left: 0.375rem;
    top: 0.125rem;
    width: 0.375rem;
    height: 0.625rem;
    border: solid white;
    border-width: 0 2px 2px 0;
    transform: rotate(45deg);
}

.custom-radio .checkmark:after {
    left: 0.3125rem;
    top: 0.3125rem;
    width: 0.5rem;
    height: 0.5rem;
    border-radius: 50%;
    background: white;
}