/* ===== RESET & BASE ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Colors */
    --primary-blue: #0066CC;
    --secondary-blue: #00AAFF;
    --dark-blue: #004999;
    --light-blue: #E6F2FF;
    --accent-blue: #0088DD;
    
    --vnpay-red: #E30A17;
    --vnpay-blue: #0066CC;
    
    --success: #10B981;
    --warning: #F59E0B;
    --error: #EF4444;
    --info: #3B82F6;
    
    --text-dark: #1F2937;
    --text-medium: #4B5563;
    --text-light: #6B7280;
    --text-white: #FFFFFF;
    
    --bg-white: #FFFFFF;
    --bg-light: #F9FAFB;
    --bg-gray: #F3F4F6;
    
    --border-light: #E5E7EB;
    --border-medium: #D1D5DB;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    
    /* Transitions */
    --transition-fast: 150ms ease-in-out;
    --transition-normal: 300ms ease-in-out;
    --transition-slow: 500ms ease-in-out;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-dark);
    background: linear-gradient(135deg, var(--primary-blue) 0%, var(--secondary-blue) 100%);
    min-height: 100vh;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* ===== HEADER ===== */
.header {
    background: var(--bg-white);
    box-shadow: var(--shadow-md);
    position: sticky;
    top: 0;
    z-index: 100;
    animation: slideDown 0.5s ease-out;
}

@keyframes slideDown {
    from {
        transform: translateY(-100%);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

.header-content {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
    padding: var(--spacing-md) 0;
}

.logo {
    height: 60px;
    width: auto;
    object-fit: contain;
    transition: transform var(--transition-normal);
}

.logo:hover {
    transform: scale(1.05);
}

.header-text {
    flex: 1;
}

.header-title {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--primary-blue);
    margin-bottom: var(--spacing-xs);
    line-height: 1.2;
}

.header-subtitle {
    font-size: 1rem;
    color: var(--text-medium);
    font-weight: 400;
}

/* ===== MAIN CONTENT ===== */
.main-content {
    padding: var(--spacing-2xl) 0;
}

/* ===== SECTION ===== */
.solution-section {
    background: var(--bg-white);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
    box-shadow: var(--shadow-xl);
    animation: fadeInUp 0.6s ease-out;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.section-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.badge {
    display: inline-block;
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: 999px;
    font-size: 0.875rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--spacing-sm);
}

.badge-recommended {
    background: linear-gradient(135deg, var(--success) 0%, #059669 100%);
    color: var(--text-white);
    box-shadow: 0 4px 12px rgba(16, 185, 129, 0.3);
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
        box-shadow: 0 4px 12px rgba(16, 185, 129, 0.3);
    }
    50% {
        transform: scale(1.05);
        box-shadow: 0 6px 16px rgba(16, 185, 129, 0.4);
    }
}

.badge-free {
    background: var(--success);
    color: var(--text-white);
    padding: 0.25rem 0.75rem;
    border-radius: 999px;
    font-size: 0.875rem;
    font-weight: 600;
}

.section-title {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-blue);
    margin-bottom: var(--spacing-sm);
    line-height: 1.2;
}

.section-subtitle {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-medium);
    margin-top: var(--spacing-sm);
}

.section-description {
    font-size: 1rem;
    color: var(--text-medium);
    max-width: 600px;
    margin: 0 auto;
}

/* ===== SOLUTION GRID ===== */
.solution-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(450px, 1fr));
    gap: var(--spacing-lg);
}

/* ===== CARD ===== */
.card {
    background: var(--bg-white);
    border: 1px solid var(--border-light);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    transition: all var(--transition-normal);
}

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

.card-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--primary-blue);
    margin-bottom: var(--spacing-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.card-title i {
    font-size: 1.125rem;
}

/* ===== DETAILS CARD ===== */
.detail-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.detail-item {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
    padding-bottom: var(--spacing-md);
    border-bottom: 1px solid var(--border-light);
}

.detail-item:last-child {
    border-bottom: none;
    padding-bottom: 0;
}

.detail-label {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-medium);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.detail-value {
    font-size: 1rem;
    color: var(--text-dark);
    font-weight: 500;
}

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

.detail-note {
    font-size: 0.875rem;
    color: var(--text-light);
    font-style: italic;
    margin-left: var(--spacing-xs);
}

.rating-good {
    color: var(--success);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.rating-good i {
    font-size: 1.125rem;
}

.rating-warning {
    color: var(--warning);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.rating-warning i {
    font-size: 1.125rem;
}

/* ===== API ENDPOINT ===== */
.api-endpoint {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    background: var(--bg-gray);
    border-radius: var(--radius-md);
    padding: var(--spacing-sm);
}

.api-endpoint-inline {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.code-block {
    flex: 1;
    font-family: 'Courier New', monospace;
    font-size: 0.875rem;
    color: var(--primary-blue);
    word-break: break-all;
    background: transparent;
    border: none;
    padding: 0;
}

code {
    font-family: 'Courier New', monospace;
    font-size: 0.875rem;
    color: var(--primary-blue);
    background: var(--bg-gray);
    padding: 0.25rem 0.5rem;
    border-radius: var(--radius-sm);
    word-break: break-all;
}

.btn-copy,
.btn-copy-small {
    background: var(--primary-blue);
    color: var(--text-white);
    border: none;
    border-radius: var(--radius-sm);
    padding: var(--spacing-xs) var(--spacing-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.btn-copy:hover,
.btn-copy-small:hover {
    background: var(--dark-blue);
    transform: scale(1.05);
}

.btn-copy:active,
.btn-copy-small:active {
    transform: scale(0.95);
}

.btn-download {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-xs) var(--spacing-md);
    background: linear-gradient(135deg, var(--success) 0%, #059669 100%);
    color: var(--text-white);
    border: none;
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    transition: all var(--transition-normal);
    box-shadow: 0 2px 8px rgba(16, 185, 129, 0.3);
}

.btn-download:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(16, 185, 129, 0.4);
}

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

.btn-download i {
    font-size: 1rem;
}

/* ===== DEMO CARD ===== */
.demo-card {
    background: linear-gradient(135deg, #F0F9FF 0%, #E0F2FE 100%);
    border: 2px solid var(--accent-blue);
}

.demo-description {
    font-size: 0.9375rem;
    color: var(--text-medium);
    margin-bottom: var(--spacing-lg);
}

.demo-form {
    margin-bottom: var(--spacing-lg);
}

.form-group {
    margin-bottom: var(--spacing-md);
}

.form-group label {
    display: block;
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: var(--spacing-xs);
}

.form-control {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 1rem;
    border: 2px solid var(--border-medium);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
    font-family: inherit;
}

.form-control:focus {
    outline: none;
    border-color: var(--primary-blue);
    box-shadow: 0 0 0 3px rgba(0, 102, 204, 0.1);
}

.form-hint {
    display: block;
    font-size: 0.8125rem;
    color: var(--text-light);
    margin-top: var(--spacing-xs);
}

/* ===== BUTTONS ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-lg);
    font-size: 1rem;
    font-weight: 600;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-normal);
    text-decoration: none;
    font-family: inherit;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-blue) 0%, var(--accent-blue) 100%);
    color: var(--text-white);
    box-shadow: 0 4px 12px rgba(0, 102, 204, 0.3);
}

.btn-primary:hover {
    box-shadow: 0 6px 16px rgba(0, 102, 204, 0.4);
    transform: translateY(-2px);
}

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

.btn-secondary {
    background: var(--bg-white);
    color: var(--primary-blue);
    border: 2px solid var(--primary-blue);
}

.btn-secondary:hover {
    background: var(--primary-blue);
    color: var(--text-white);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-search {
    width: 100%;
    position: relative;
}

.btn-search.loading .btn-text {
    opacity: 0;
}

.btn-search.loading .btn-loader {
    display: block;
}

.btn-loader {
    display: none;
    position: absolute;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-top-color: white;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

.btn-close {
    background: transparent;
    border: none;
    color: var(--text-light);
    cursor: pointer;
    padding: var(--spacing-xs);
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
}

.btn-close:hover {
    background: var(--bg-gray);
    color: var(--text-dark);
}

/* ===== TOKEN STATUS ===== */
.token-status {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--light-blue);
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    color: var(--primary-blue);
    margin-bottom: var(--spacing-md);
}

.token-status.active {
    background: #D1FAE5;
    color: var(--success);
}

.token-status.expired {
    background: #FEE2E2;
    color: var(--error);
}

.token-status.refreshing {
    background: #FEF3C7;
    color: var(--warning);
}

/* ===== RESULT CONTAINER ===== */
.result-container {
    margin-top: var(--spacing-lg);
    border: 2px solid var(--primary-blue);
    border-radius: var(--radius-lg);
    overflow: hidden;
    animation: slideIn 0.3s ease-out;
}

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

.result-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-md);
    background: linear-gradient(135deg, var(--primary-blue) 0%, var(--accent-blue) 100%);
    color: var(--text-white);
}

.result-header h5 {
    font-size: 1.125rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin: 0;
}

.result-content {
    padding: var(--spacing-lg);
    background: var(--bg-white);
    max-height: 500px;
    overflow-y: auto;
}

.result-item {
    display: grid;
    grid-template-columns: 200px 1fr;
    gap: var(--spacing-md);
    padding: var(--spacing-sm) 0;
    border-bottom: 1px solid var(--border-light);
}

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

.result-label {
    font-weight: 600;
    color: var(--text-medium);
    font-size: 0.9375rem;
}

.result-value {
    color: var(--text-dark);
    font-size: 0.9375rem;
}

.result-error {
    padding: var(--spacing-lg);
    background: #FEE2E2;
    color: var(--error);
    border-radius: var(--radius-md);
    text-align: center;
}

.result-error i {
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
}

.result-error h4 {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-sm);
}

.result-error p {
    font-size: 0.9375rem;
    opacity: 0.9;
}

.cors-error-detailed {
    padding: var(--spacing-lg);
    text-align: center;
}

.cors-error-detailed h4 {
    color: var(--warning);
    font-size: 1.25rem;
    margin-bottom: var(--spacing-sm);
}

.cors-error-detailed h5 {
    font-size: 1rem;
    margin-bottom: var(--spacing-xs);
    color: var(--text-dark);
}

.cors-error-detailed ul {
    text-align: left;
    line-height: 1.8;
}

.cors-error-detailed ul li {
    margin-bottom: 0.25rem;
}

.cors-error-detailed .btn {
    margin: 0.25rem;
}

/* ===== OTHER SOLUTIONS ===== */
.other-solutions-section {
    background: var(--bg-white);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-xl);
    animation: fadeInUp 0.8s ease-out;
}

/* ===== ACCORDION ===== */
.accordion {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.accordion-item {
    border: 1px solid var(--border-light);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: all var(--transition-normal);
}

.accordion-item:hover {
    box-shadow: var(--shadow-md);
}

.accordion-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--bg-light);
    cursor: pointer;
    transition: all var(--transition-fast);
    user-select: none;
}

.accordion-header:hover {
    background: var(--light-blue);
}

.accordion-item.active .accordion-header {
    background: linear-gradient(135deg, var(--primary-blue) 0%, var(--accent-blue) 100%);
    color: var(--text-white);
}

.accordion-title {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    font-size: 1.125rem;
    font-weight: 600;
}

.accordion-title i {
    font-size: 1.25rem;
}

.accordion-icon {
    transition: transform var(--transition-normal);
    font-size: 1.25rem;
}

.accordion-item.active .accordion-icon {
    transform: rotate(180deg);
}

.accordion-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-slow);
}

.accordion-item.active .accordion-content {
    max-height: 1000px;
}

.solution-details {
    padding: var(--spacing-lg);
}

.detail-row {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
    padding: var(--spacing-md) 0;
    border-bottom: 1px solid var(--border-light);
}

.detail-row:last-of-type {
    border-bottom: none;
}

.detail-row .label {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-medium);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.detail-row .value {
    font-size: 1rem;
    color: var(--text-dark);
}

.action-buttons {
    display: flex;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-lg);
    padding-top: var(--spacing-lg);
    border-top: 2px solid var(--border-light);
}

/* ===== TOAST ===== */
#toast-container {
    position: fixed;
    top: var(--spacing-lg);
    right: var(--spacing-lg);
    z-index: 1000;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.toast {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--bg-white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
    min-width: 300px;
    max-width: 400px;
    animation: slideInRight 0.3s ease-out;
}

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

.toast.removing {
    animation: slideOutRight 0.3s ease-out forwards;
}

@keyframes slideOutRight {
    to {
        opacity: 0;
        transform: translateX(100%);
    }
}

.toast-icon {
    font-size: 1.5rem;
    flex-shrink: 0;
}

.toast-content {
    flex: 1;
}

.toast-title {
    font-weight: 600;
    font-size: 0.9375rem;
    margin-bottom: 0.25rem;
}

.toast-message {
    font-size: 0.875rem;
    opacity: 0.9;
}

.toast.success {
    border-left: 4px solid var(--success);
}

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

.toast.error {
    border-left: 4px solid var(--error);
}

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

.toast.info {
    border-left: 4px solid var(--info);
}

.toast.info .toast-icon {
    color: var(--info);
}

.toast.warning {
    border-left: 4px solid var(--warning);
}

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

/* ===== FOOTER ===== */
.footer {
    background: var(--bg-white);
    padding: var(--spacing-lg) 0;
    margin-top: var(--spacing-2xl);
    box-shadow: 0 -4px 6px -1px rgba(0, 0, 0, 0.1);
}

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

.copyright {
    font-size: 0.9375rem;
    color: var(--text-medium);
    margin-bottom: var(--spacing-xs);
}

.update-date {
    font-size: 0.875rem;
    color: var(--text-light);
}

/* ===== RESPONSIVE ===== */
@media (max-width: 1024px) {
    .solution-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .header-content {
        flex-direction: column;
        text-align: center;
        gap: var(--spacing-md);
    }
    
    .logo {
        height: 50px;
    }
    
    .header-title {
        font-size: 1.5rem;
    }
    
    .header-subtitle {
        font-size: 0.9375rem;
    }
    
    .section-title {
        font-size: 1.5rem;
    }
    
    .section-subtitle {
        font-size: 1.125rem;
    }
    
    .solution-section,
    .other-solutions-section {
        padding: var(--spacing-lg);
    }
    
    .result-item {
        grid-template-columns: 1fr;
        gap: var(--spacing-xs);
    }
    
    .accordion-title {
        font-size: 1rem;
    }
    
    .action-buttons {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
    }
    
    #toast-container {
        top: var(--spacing-sm);
        right: var(--spacing-sm);
        left: var(--spacing-sm);
    }
    
    .toast {
        min-width: auto;
        max-width: none;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--spacing-sm);
    }
    
    .header-title {
        font-size: 1.25rem;
    }
    
    .section-title {
        font-size: 1.25rem;
    }
    
    .card-title {
        font-size: 1.125rem;
    }
    
    .solution-section,
    .other-solutions-section {
        padding: var(--spacing-md);
    }
}

/* ===== UTILITY CLASSES ===== */
.text-center {
    text-align: center;
}

.mt-1 { margin-top: var(--spacing-xs); }
.mt-2 { margin-top: var(--spacing-sm); }
.mt-3 { margin-top: var(--spacing-md); }
.mt-4 { margin-top: var(--spacing-lg); }

.mb-1 { margin-bottom: var(--spacing-xs); }
.mb-2 { margin-bottom: var(--spacing-sm); }
.mb-3 { margin-bottom: var(--spacing-md); }
.mb-4 { margin-bottom: var(--spacing-lg); }

.hidden {
    display: none !important;
}

/* ===== SCROLLBAR ===== */
::-webkit-scrollbar {
    width: 10px;
    height: 10px;
}

::-webkit-scrollbar-track {
    background: var(--bg-gray);
    border-radius: var(--radius-sm);
}

::-webkit-scrollbar-thumb {
    background: var(--primary-blue);
    border-radius: var(--radius-sm);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--dark-blue);
}