/* Arithmetic Sequence Calculator Styles */
.sequence-calculator {
    margin-top: 2rem;
}

.calculator-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin-bottom: 2rem;
}

.input-panel {
    background: #ffffff;
    border-radius: 16px;
    padding: 2rem;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05), 0 1px 2px rgba(0, 0, 0, 0.1);
    border: 1px solid #e5e7eb;
}

.panel-header {
    margin-bottom: 2rem;
    padding-bottom: 1.5rem;
    border-bottom: 2px solid #f3f4f6;
}

.panel-title {
    font-size: 1.5rem;
    font-weight: 700;
    color: #111827;
    margin: 0 0 0.5rem 0;
    line-height: 1.3;
}

.panel-description {
    font-size: 0.875rem;
    color: #6b7280;
    margin: 0;
    line-height: 1.5;
}

.input-fields {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.field-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.field-label {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.label-text {
    font-size: 0.875rem;
    font-weight: 600;
    color: #374151;
    letter-spacing: 0.01em;
}

.label-hint {
    font-size: 0.75rem;
    color: #9ca3af;
    font-weight: 400;
}

.field-input {
    width: 100%;
    padding: 0.875rem 1rem;
    font-size: 1rem;
    border: 2px solid #e5e7eb;
    border-radius: 8px;
    background: #ffffff;
    color: #111827;
    transition: all 0.2s ease;
    font-weight: 500;
}

.field-input:focus {
    outline: none;
    border-color: #6366f1;
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
    background: #fafafa;
}

.field-input:hover:not(:focus) {
    border-color: #d1d5db;
}

.field-input::placeholder {
    color: #9ca3af;
    font-weight: 400;
}

.optional-section {
    margin-top: 0.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid #f3f4f6;
}

.optional-header {
    margin-bottom: 1rem;
}

.optional-badge {
    display: inline-block;
    font-size: 0.75rem;
    font-weight: 600;
    color: #6366f1;
    background: #eef2ff;
    padding: 0.375rem 0.75rem;
    border-radius: 6px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.action-buttons {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    margin-top: 2rem;
    padding-top: 1.5rem;
    border-top: 2px solid #f3f4f6;
}

.btn {
    padding: 0.875rem 1.5rem;
    font-size: 0.9375rem;
    font-weight: 600;
    border-radius: 8px;
    border: none;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    text-transform: none;
    letter-spacing: 0;
}

.btn-primary {
    background: #6366f1;
    color: #ffffff;
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.05);
}

.btn-primary:hover {
    background: #4f46e5;
    transform: translateY(-1px);
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-secondary {
    background: #ffffff;
    color: #6b7280;
    border: 2px solid #e5e7eb;
}

.btn-secondary:hover {
    background: #f9fafb;
    border-color: #d1d5db;
    color: #374151;
}

.btn-icon {
    display: none;
}

.results-panel {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.results-container {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 16px;
    padding: 2rem;
    color: #ffffff;
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    min-height: 300px;
    display: flex;
    flex-direction: column;
}

.results-placeholder {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 2rem;
}

.placeholder-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
    opacity: 0.8;
}

.placeholder-title {
    font-size: 1.25rem;
    font-weight: 700;
    margin: 0 0 0.5rem 0;
    color: #ffffff;
}

.placeholder-text {
    font-size: 0.875rem;
    color: rgba(255, 255, 255, 0.9);
    margin: 0;
    max-width: 280px;
    line-height: 1.5;
}

.results-content {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.result-main {
    text-align: center;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.2);
}

.result-label {
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: 0.5rem;
    display: block;
}

.result-value {
    font-size: 2rem;
    font-weight: 800;
    line-height: 1.2;
    color: #ffffff;
    word-break: break-word;
}

.result-details {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.result-detail {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

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

.detail-label {
    font-size: 0.875rem;
    color: rgba(255, 255, 255, 0.9);
    font-weight: 500;
}

.detail-value {
    font-size: 1.125rem;
    font-weight: 700;
    color: #ffffff;
    text-align: right;
}

.sequence-display {
    background: #ffffff;
    border-radius: 16px;
    padding: 1.5rem;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05), 0 1px 2px rgba(0, 0, 0, 0.1);
    border: 1px solid #e5e7eb;
}

.display-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid #f3f4f6;
}

.display-title {
    font-size: 1.125rem;
    font-weight: 700;
    color: #111827;
    margin: 0;
}

.copy-btn {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
    font-weight: 600;
    color: #6366f1;
    background: #eef2ff;
    border: 1px solid #c7d2fe;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.2s ease;
}

.copy-btn:hover {
    background: #6366f1;
    color: #ffffff;
    border-color: #6366f1;
}

.sequence-items {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.sequence-item {
    display: inline-flex;
    align-items: center;
    padding: 0.5rem 1rem;
    background: #6366f1;
    color: #ffffff;
    border-radius: 8px;
    font-size: 0.875rem;
    font-weight: 600;
    animation: fadeInScale 0.3s ease-out;
}

@keyframes fadeInScale {
    from {
        opacity: 0;
        transform: scale(0.9);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

.formula-section {
    margin-top: 2rem;
}

.formula-card {
    background: #f9fafb;
    border-radius: 16px;
    padding: 2rem;
    border: 1px solid #e5e7eb;
}

.formula-title {
    font-size: 1.25rem;
    font-weight: 700;
    color: #111827;
    margin: 0 0 1.5rem 0;
}

.formula-list {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.formula-item {
    padding: 1.5rem;
    background: #ffffff;
    border-radius: 12px;
    border: 1px solid #e5e7eb;
}

.formula-name {
    font-size: 0.875rem;
    font-weight: 600;
    color: #6b7280;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.75rem;
}

.formula-equation {
    font-size: 1.25rem;
    font-weight: 700;
    color: #111827;
    
    letter-spacing: 0.02em;
}

.toast-notification {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    background: #10b981;
    color: #ffffff;
    padding: 1rem 1.5rem;
    border-radius: 8px;
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    display: none;
    align-items: center;
    gap: 0.75rem;
    z-index: 9999;
    animation: slideInUp 0.3s ease-out;
    max-width: 320px;
}

.toast-notification.error {
    background: #ef4444;
}

.toast-message {
    font-size: 0.875rem;
    font-weight: 500;
    line-height: 1.5;
}

@keyframes slideInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Mobile Responsive Styles */
@media (max-width: 992px) {
    .calculator-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }

    .input-panel {
        padding: 1.5rem;
    }

    .results-container {
        min-height: 250px;
        padding: 1.5rem;
    }
}

@media (max-width: 768px) {
    .sequence-calculator {
        margin-top: 1.5rem;
    }

    .panel-title {
        font-size: 1.25rem;
    }

    .panel-description {
        font-size: 0.8125rem;
    }

    .input-panel {
        padding: 1.25rem;
    }

    .action-buttons {
        grid-template-columns: 1fr;
        gap: 0.75rem;
    }

    .btn {
        padding: 0.75rem 1.25rem;
        font-size: 0.875rem;
    }

    .results-container {
        padding: 1.25rem;
        min-height: 200px;
    }

    .result-value {
        font-size: 1.5rem;
    }

    .sequence-display {
        padding: 1.25rem;
    }

    .formula-card {
        padding: 1.5rem;
    }

    .formula-equation {
        font-size: 1.125rem;
    }

    .toast-notification {
        bottom: 1rem;
        right: 1rem;
        left: 1rem;
        max-width: none;
    }
}

@media (max-width: 480px) {
    .field-input {
        padding: 0.75rem 0.875rem;
        font-size: 0.9375rem;
    }

    .result-value {
        font-size: 1.25rem;
    }

    .sequence-item {
        font-size: 0.8125rem;
        padding: 0.4375rem 0.875rem;
    }

    .formula-card {
        padding: 1.25rem;
    }
}