/* CSS Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #2196F3;
    --success-color: #4CAF50;
    --warning-color: #FFC107;
    --error-color: #F44336;
    --accent-color: #9C27B0;
    --bg-color: #f5f7fa;
    --card-bg: #ffffff;
    --text-primary: #333333;
    --text-secondary: #666666;
    --text-light: #999999;
    --border-color: #e1e5e9;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-hover: 0 4px 16px rgba(0, 0, 0, 0.15);
    --border-radius: 8px;
    --transition: all 0.3s ease;
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
}

body {
    font-family: var(--font-family);
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

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

/* Header Styles */
.header {
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    color: white;
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow);
}

.header__content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.header__title {
    font-size: 1.8rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.header__icon {
    font-size: 2rem;
    color: var(--warning-color);
}

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

.nav-btn {
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.9rem;
    font-weight: 500;
}

.nav-btn:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: translateY(-1px);
}

.nav-btn--active {
    background: rgba(255, 255, 255, 0.3);
    border-color: rgba(255, 255, 255, 0.4);
}

/* Main Content */
.main {
    flex: 1;
    padding: 2rem 0;
}

.section {
    display: none;
    animation: fadeIn 0.3s ease-in-out;
}

.section--active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.section__title {
    font-size: 2rem;
    margin-bottom: 2rem;
    color: var(--text-primary);
    text-align: center;
}

/* Portfolio Summary */
.portfolio-summary {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.summary-card {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    text-align: center;
    transition: var(--transition);
}

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

.summary-card__title {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.summary-card__value {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--text-primary);
}

.summary-card__value.positive {
    color: var(--success-color);
}

.summary-card__value.negative {
    color: var(--error-color);
}

/* Portfolio Assets */
.portfolio-assets {
    display: grid;
    gap: 1rem;
}

.asset-card {
    background: var(--card-bg);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    overflow: hidden;
    transition: var(--transition);
}

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

.asset-card__header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.asset-card__info {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.asset-card__icon {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 700;
    font-size: 1.2rem;
}

.asset-card__name {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-primary);
}

.asset-card__symbol {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.asset-card__price {
    text-align: right;
}

.asset-card__current-price {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
}

.asset-card__change {
    font-size: 0.9rem;
    font-weight: 500;
}

.asset-card__change.positive {
    color: var(--success-color);
}

.asset-card__change.negative {
    color: var(--error-color);
}

.asset-card__body {
    padding: 1.5rem;
}

.asset-card__stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 1rem;
}

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

.asset-stat__label {
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-bottom: 0.25rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.asset-stat__value {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
}

.asset-stat__value.positive {
    color: var(--success-color);
}

.asset-stat__value.negative {
    color: var(--error-color);
}

/* Form Styles */
.form-container {
    max-width: 600px;
    margin: 0 auto;
    background: var(--card-bg);
    padding: 2rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
}

.asset-form {
    display: grid;
    gap: 1.5rem;
}

.form-group {
    display: flex;
    flex-direction: column;
}

.form-label {
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.form-input {
    padding: 0.75rem;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
    background: white;
}

.form-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(33, 150, 243, 0.1);
}

.form-input:invalid {
    border-color: var(--error-color);
}

/* Button Styles */
.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

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

.btn--primary:hover {
    background: #1976D2;
    transform: translateY(-1px);
    box-shadow: var(--shadow-hover);
}

.btn--danger {
    background: var(--error-color);
    color: white;
    padding: 0.5rem;
    font-size: 0.9rem;
}

.btn--danger:hover {
    background: #D32F2F;
}

.btn--full {
    width: 100%;
}

/* History Styles */
.history-container {
    display: grid;
    gap: 1rem;
}

.transaction-card {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: var(--transition);
}

.transaction-card:hover {
    box-shadow: var(--shadow-hover);
}

.transaction-info {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.transaction-icon {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 700;
}

.transaction-details h4 {
    font-size: 1.1rem;
    margin-bottom: 0.25rem;
}

.transaction-details p {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.transaction-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.transaction-value {
    text-align: right;
}

.transaction-amount {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.transaction-date {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

/* FAQ Styles */
.faq-container {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    background: var(--card-bg);
    border-radius: var(--border-radius);
    margin-bottom: 1rem;
    box-shadow: var(--shadow);
    overflow: hidden;
}

.faq-question {
    width: 100%;
    padding: 1.5rem;
    background: none;
    border: none;
    text-align: left;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: var(--transition);
}

.faq-question:hover {
    background: var(--bg-color);
}

.faq-icon {
    font-size: 1.5rem;
    color: var(--primary-color);
    transition: var(--transition);
}

.faq-item.active .faq-icon {
    transform: rotate(45deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
}

.faq-item.active .faq-answer {
    max-height: 200px;
}

.faq-answer p {
    padding: 0 1.5rem 1.5rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 3rem 1rem;
    background: var(--card-bg);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
}

.empty-state__icon {
    font-size: 4rem;
    margin-bottom: 1rem;
    opacity: 0.5;
}

.empty-state__title {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.empty-state__text {
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

/* Loading Overlay */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    display: none;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    flex-direction: column;
    gap: 1rem;
    color: white;
}

.loading-overlay.active {
    display: flex;
}

.loading-spinner {
    width: 50px;
    height: 50px;
    border: 4px solid rgba(255, 255, 255, 0.3);
    border-top: 4px solid white;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Toast Notifications */
.toast-container {
    position: fixed;
    top: 100px;
    right: 20px;
    z-index: 1001;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.toast {
    background: var(--card-bg);
    padding: 1rem 1.5rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-hover);
    border-left: 4px solid var(--primary-color);
    min-width: 300px;
    animation: slideIn 0.3s ease;
    position: relative;
}

.toast.success {
    border-left-color: var(--success-color);
}

.toast.error {
    border-left-color: var(--error-color);
}

.toast.warning {
    border-left-color: var(--warning-color);
}

@keyframes slideIn {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

/* Footer */
.footer {
    background: var(--text-primary);
    color: white;
    padding: 1rem 0;
    text-align: center;
    margin-top: auto;
}

.footer__text {
    font-size: 0.9rem;
    opacity: 0.8;
}
.footer_link {
    color: white;
    text-decoration: none;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 0 15px;
    }
    
    .header__content {
        flex-direction: column;
        text-align: center;
    }
    
    .header__nav {
        justify-content: center;
    }
    
    .nav-btn {
        font-size: 0.8rem;
        padding: 0.4rem 0.8rem;
    }
    
    .portfolio-summary {
        grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
        gap: 1rem;
    }
    
    .summary-card {
        padding: 1rem;
    }
    
    .summary-card__value {
        font-size: 1.5rem;
    }
    
    .asset-card__header {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }
    
    .asset-card__stats {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .form-container {
        padding: 1.5rem;
    }
    
    .section__title {
        font-size: 1.5rem;
    }
    
    .transaction-card {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }
    
    .transaction-actions {
        justify-content: center;
    }
    
    .toast {
        min-width: auto;
        width: calc(100vw - 40px);
    }
    
    .toast-container {
        right: 20px;
        left: 20px;
    }
}

@media (max-width: 480px) {
    .main {
        padding: 1rem 0;
    }
    
    .portfolio-summary {
        grid-template-columns: 1fr;
    }
    
    .asset-card__stats {
        grid-template-columns: 1fr;
    }
    
    .form-container {
        padding: 1rem;
    }
    
    .header__title {
        font-size: 1.5rem;
    }
    
    .nav-btn {
        flex: 1;
        min-width: 70px;
    }
}

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

/* Focus styles for keyboard navigation */
.nav-btn:focus,
.btn:focus,
.form-input:focus,
.faq-question:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    :root {
        --shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
        --border-color: #000000;
    }
}