/* Reset and base styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --tg-theme-bg-color: #ffffff;
    --tg-theme-text-color: #000000;
    --tg-theme-hint-color: #999999;
    --tg-theme-link-color: #3390ec;
    --tg-theme-button-color: #3390ec;
    --tg-theme-button-text-color: #ffffff;
    --tg-theme-secondary-bg-color: #f1f1f1;
    
    --primary-color: #3390ec;
    --primary-hover: #2a7dd1;
    --border-color: #e0e0e0;
    --success-color: #4caf50;
    --warning-color: #ff9800;
    --error-color: #f44336;
    
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    
    --border-radius: 12px;
    --border-radius-sm: 8px;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 4px 16px rgba(0, 0, 0, 0.15);
}

/* Dark theme support */
@media (prefers-color-scheme: dark) {
    :root {
        --tg-theme-bg-color: #212121;
        --tg-theme-text-color: #ffffff;
        --tg-theme-hint-color: #707579;
        --tg-theme-secondary-bg-color: #181818;
        --border-color: #333333;
    }
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--tg-theme-bg-color);
    color: var(--tg-theme-text-color);
    line-height: 1.6;
    padding: var(--spacing-sm);
    max-width: 600px;
    margin: 0 auto;
    min-height: 100vh;
}

.container {
    background-color: var(--tg-theme-bg-color);
}

/* Header */
header {
    text-align: center;
    padding: var(--spacing-lg) var(--spacing-sm);
    margin-bottom: var(--spacing-md);
}

header h1 {
    font-size: 2rem;
    margin-bottom: var(--spacing-xs);
    color: var(--tg-theme-text-color);
}

.subtitle {
    color: var(--tg-theme-hint-color);
    font-size: 0.9rem;
}

/* Language switcher */
.lang-switcher {
    display: flex;
    justify-content: center;
    gap: var(--spacing-xs);
    margin-top: var(--spacing-sm);
}

.lang-switcher .lang-btn {
    padding: var(--spacing-xs) var(--spacing-sm);
    font-size: 0.8rem;
    font-weight: 500;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    background-color: var(--tg-theme-secondary-bg-color);
    color: var(--tg-theme-text-color);
    cursor: pointer;
    transition: background-color 0.2s, border-color 0.2s, color 0.2s;
}

.lang-switcher .lang-btn:hover {
    background-color: var(--border-color);
}

.lang-switcher .lang-btn.active {
    background-color: var(--primary-color);
    border-color: var(--primary-color);
    color: var(--tg-theme-button-text-color);
}

/* Tabs */
.tabs {
    display: flex;
    gap: var(--spacing-xs);
    margin-bottom: var(--spacing-md);
    overflow-x: auto;
    padding-bottom: var(--spacing-xs);
    scrollbar-width: none;
    -ms-overflow-style: none;
}

.tabs::-webkit-scrollbar {
    display: none;
}

.tab-btn {
    flex: 1;
    min-width: fit-content;
    padding: var(--spacing-xs) var(--spacing-sm);
    background-color: var(--tg-theme-secondary-bg-color);
    border: none;
    border-radius: var(--border-radius-sm);
    color: var(--tg-theme-text-color);
    font-size: 0.85rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    white-space: nowrap;
}

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

.tab-btn.active {
    background-color: var(--primary-color);
    color: var(--tg-theme-button-text-color);
}

/* Tab content */
.tab-content {
    display: none;
    animation: fadeIn 0.3s ease-in;
}

.tab-content.active {
    display: block;
}

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

/* Sections */
.section {
    margin-bottom: var(--spacing-lg);
    padding: var(--spacing-md);
    background-color: var(--tg-theme-secondary-bg-color);
    border-radius: var(--border-radius);
}

.section h2 {
    font-size: 1.3rem;
    margin-bottom: var(--spacing-sm);
    color: var(--tg-theme-text-color);
}

.section h3 {
    font-size: 1.1rem;
    margin-top: var(--spacing-sm);
    margin-bottom: var(--spacing-xs);
    color: var(--tg-theme-text-color);
}

.section p {
    margin-bottom: var(--spacing-sm);
    color: var(--tg-theme-text-color);
}

.section ul, .section ol {
    margin-left: var(--spacing-md);
    margin-bottom: var(--spacing-sm);
}

.section li {
    margin-bottom: var(--spacing-xs);
    color: var(--tg-theme-text-color);
}

.section code {
    background-color: var(--tg-theme-bg-color);
    padding: 0.2rem 0.4rem;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    font-size: 0.9em;
    color: var(--primary-color);
}

/* Info boxes */
.info-box {
    background-color: var(--tg-theme-bg-color);
    padding: var(--spacing-sm);
    border-radius: var(--border-radius-sm);
    margin: var(--spacing-sm) 0;
    border-left: 3px solid var(--primary-color);
}

.info-box.highlight {
    background-color: rgba(51, 144, 236, 0.1);
    border-left-color: var(--primary-color);
}

.info-box strong {
    color: var(--primary-color);
}

/* Accordion */
.accordion {
    margin: var(--spacing-sm) 0;
}

.accordion-item {
    margin-bottom: var(--spacing-xs);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    overflow: hidden;
}

.accordion-header {
    width: 100%;
    padding: var(--spacing-sm);
    background-color: var(--tg-theme-secondary-bg-color);
    border: none;
    text-align: left;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 1rem;
    color: var(--tg-theme-text-color);
    transition: background-color 0.2s;
}

.accordion-header:hover {
    background-color: var(--border-color);
}

.accordion-icon {
    transition: transform 0.3s;
    font-size: 0.8rem;
    color: var(--tg-theme-hint-color);
}

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

.accordion-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease-out;
    background-color: var(--tg-theme-bg-color);
}

.accordion-item.active .accordion-content {
    max-height: 1000px;
    padding: var(--spacing-sm);
}

.accordion-content p,
.accordion-content ul,
.accordion-content ol {
    margin-bottom: var(--spacing-sm);
}

/* Calculator form */
.calculator-form {
    margin-top: var(--spacing-md);
}

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

.form-group label {
    display: block;
    margin-bottom: var(--spacing-xs);
    font-weight: 500;
    color: var(--tg-theme-text-color);
}

.form-group input,
.form-group select {
    width: 100%;
    padding: var(--spacing-sm);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    background-color: var(--tg-theme-bg-color);
    color: var(--tg-theme-text-color);
    font-size: 1rem;
    transition: border-color 0.2s;
}

.form-group input:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--primary-color);
}

.btn-primary {
    width: 100%;
    padding: var(--spacing-sm);
    background-color: var(--primary-color);
    color: var(--tg-theme-button-text-color);
    border: none;
    border-radius: var(--border-radius-sm);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s;
    margin-top: var(--spacing-md);
}

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

.btn-primary:active {
    transform: scale(0.98);
}

/* Calculator result */
.calculator-result {
    margin-top: var(--spacing-lg);
    padding: var(--spacing-md);
    background-color: var(--tg-theme-secondary-bg-color);
    border-radius: var(--border-radius);
    animation: slideUp 0.3s ease-out;
}

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

.result-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-sm);
    margin-top: var(--spacing-md);
}

.result-item {
    background-color: var(--tg-theme-bg-color);
    padding: var(--spacing-sm);
    border-radius: var(--border-radius-sm);
    text-align: center;
    border: 1px solid var(--border-color);
}

.result-label {
    font-size: 0.85rem;
    color: var(--tg-theme-hint-color);
    margin-bottom: var(--spacing-xs);
}

.result-value {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--primary-color);
    margin: var(--spacing-xs) 0;
}

.result-unit {
    font-size: 0.85rem;
    color: var(--tg-theme-hint-color);
}

/* Responsive */
@media (max-width: 480px) {
    .result-grid {
        grid-template-columns: 1fr;
    }
    
    .tabs {
        gap: 0.25rem;
    }
    
    .tab-btn {
        font-size: 0.75rem;
        padding: 0.4rem 0.6rem;
    }
}

/* Loading state */
.loading {
    opacity: 0.6;
    pointer-events: none;
    text-align: center;
    padding: var(--spacing-lg);
    color: var(--tg-theme-hint-color);
}

/* Page container for SPA */
.page {
    min-height: 100vh;
}

/* Hide pages by default (will be shown by router) */
.page:not(:first-child) {
    display: none;
}

/* Payment methods styles */
#payment-methods {
    padding: var(--spacing-md);
}

#payment-methods .error {
    text-align: center;
    padding: var(--spacing-lg);
    color: var(--error-color);
}

.methods-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.method-btn {
    display: flex;
    align-items: center;
    padding: var(--spacing-md);
    background-color: var(--tg-theme-secondary-bg-color);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: all 0.2s;
    width: 100%;
    text-align: left;
}

.method-btn:active {
    background-color: var(--tg-theme-button-color);
    transform: scale(0.98);
}

.method-icon {
    font-size: 1.5rem;
    margin-right: var(--spacing-sm);
}

.method-name {
    flex: 1;
    font-size: 1rem;
    font-weight: 500;
    color: var(--tg-theme-text-color);
}

.method-arrow {
    color: var(--tg-theme-hint-color);
    font-size: 1.2rem;
}