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

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: 'Poppins', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: #2d3748;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 50%, #f093fb 100%);
    min-height: 100vh;
    overflow-x: hidden;
    font-weight: 400;
    letter-spacing: -0.01em;
}

/* ===== CSS Variables ===== */
:root {
    /* Colors - Modern Purple & Blue Theme */
    --color-primary: #667eea;
    --color-secondary: #764ba2;
    --color-accent: #f093fb;
    --color-success: #48bb78;
    --color-warning: #ed8936;
    --color-error: #f56565;
    
    --color-bg-primary: rgba(255, 255, 255, 0.95);
    --color-bg-secondary: rgba(255, 255, 255, 0.8);
    --color-bg-tertiary: rgba(255, 255, 255, 0.6);
    --color-bg-overlay: rgba(102, 126, 234, 0.9);
    
    --color-text-primary: #2d3748;
    --color-text-secondary: #4a5568;
    --color-text-muted: #718096;
    --color-text-light: #a0aec0;
    
    --color-border: rgba(102, 126, 234, 0.2);
    --color-border-hover: rgba(102, 126, 234, 0.4);
    --color-shadow: rgba(102, 126, 234, 0.15);
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    
    /* Shadows */
    --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --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);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    --shadow-glow: 0 0 20px rgba(102, 126, 234, 0.3);
    
    /* Transitions */
    --transition-fast: 0.15s ease-in-out;
    --transition-normal: 0.3s ease-in-out;
    --transition-slow: 0.5s ease-in-out;
}

/* ===== Loading Overlay ===== */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--color-bg-overlay);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
    opacity: 1;
    visibility: visible;
    transition: opacity var(--transition-normal), visibility var(--transition-normal);
}

.loading-overlay.hidden {
    opacity: 0;
    visibility: hidden;
}

.loading-spinner {
    text-align: center;
    color: white;
}

.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;
    margin: 0 auto var(--spacing-md);
}

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

.loading-text {
    font-size: 1.1rem;
    font-weight: 500;
}

/* ===== Container ===== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ===== Header ===== */
.header {
    padding: var(--spacing-2xl) 0;
    text-align: center;
    background: var(--color-bg-primary);
    border-radius: var(--radius-xl);
    margin: var(--spacing-lg) 0;
    box-shadow: var(--shadow-md);
}

.header__title {
    font-family: 'Poppins', sans-serif;
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
    letter-spacing: -0.03em;
}

.header__subtitle {
    font-family: 'Inter', sans-serif;
    font-size: 1.125rem;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-lg);
    font-weight: 400;
    letter-spacing: -0.005em;
}

.header__update-time {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--color-bg-tertiary);
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    color: var(--color-text-muted);
}

.update-time__value {
    font-weight: 600;
    color: var(--color-accent);
}

/* ===== Main Content ===== */
.main {
    flex: 1;
    padding: var(--spacing-xl) 0;
    background: linear-gradient(135deg, var(--color-bg-primary) 0%, var(--color-bg-secondary) 100%);
    min-height: calc(100vh - 200px);
    display: flex;
    align-items: center;
    justify-content: center;
}

/* ===== Converter Section ===== */
.converter {
    width: 100%;
    max-width: 800px;
    margin: 10px auto 0;
    padding: 0 var(--spacing-lg);
}

.converter__container {
    background: var(--color-bg-primary);
    border-radius: var(--radius-xl);
    padding: var(--spacing-3xl);
    box-shadow: var(--shadow-2xl), var(--shadow-glow);
    border: 1px solid var(--color-border);
    position: relative;
    overflow: hidden;
    backdrop-filter: blur(10px);
    transition: all var(--transition-normal);
    animation: slideInUp 0.8s ease-out;
}

.converter__container:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-2xl), 0 0 30px rgba(102, 126, 234, 0.4);
}

.converter__container::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--color-primary), var(--color-secondary), var(--color-accent));
}

.converter__title {
    font-family: 'Poppins', sans-serif;
    font-size: 2.25rem;
    font-weight: 700;
    color: var(--color-text-primary);
    text-align: center;
    margin-bottom: var(--spacing-3xl);
    position: relative;
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary), var(--color-accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.02em;
}

.converter__title .worldfirst-gradient {
    background: linear-gradient(135deg, #ff6b6b, #ee5a24, #d63031);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-weight: 700;
}

.converter__title::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 3px;
    background: linear-gradient(90deg, var(--color-primary), var(--color-secondary), var(--color-accent));
    border-radius: 2px;
}

.converter__input-group {
    margin-bottom: var(--spacing-xxl);
    position: relative;
}

.input-group__label {
    font-family: 'Inter', sans-serif;
    display: block;
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--color-text-primary);
    margin-bottom: var(--spacing-md);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    position: relative;
    padding-left: 12px;
}

.input-group__label::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 4px;
    height: 16px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary), var(--color-accent));
    border-radius: 2px;
}

.input-group__content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: var(--spacing-md);
}

.currency-select,
.amount-input {
    padding: var(--spacing-lg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    font-size: 1.1rem;
    font-weight: 600;
    background: var(--color-bg-primary);
    color: var(--color-text-primary);
    transition: all var(--transition-normal);
    box-shadow: var(--shadow-sm);
    backdrop-filter: blur(5px);
}

.currency-select:hover,
.amount-input:hover {
    border-color: var(--color-secondary);
    box-shadow: var(--shadow-md);
    transform: translateY(-1px);
}

.currency-select:focus,
.amount-input:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 4px rgba(102, 126, 234, 0.15), var(--shadow-md);
    transform: translateY(-2px);
}

.currency-select:hover,
.amount-input:hover {
    border-color: var(--color-primary);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
    transform: translateY(-1px);
}

.currency-select {
    cursor: pointer;
    background-image: url('data:image/svg+xml;charset=US-ASCII,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 4 5"><path fill="%23666" d="M2 0L0 2h4zm0 5L0 3h4z"/></svg>');
    background-repeat: no-repeat;
    background-position: right 12px center;
    background-size: 12px;
    padding-right: 40px;
}

.currency-select:disabled {
    background-color: var(--color-bg-secondary);
    color: var(--color-text-muted);
    cursor: not-allowed;
    opacity: 0.7;
}

.currency-text {
    display: inline-block;
    padding: var(--spacing-lg);
    background-color: var(--color-bg-secondary);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-lg);
    font-size: 1.1rem;
    color: var(--color-text-primary);
    font-weight: 600;
    box-sizing: border-box;
}

.amount-input[readonly] {
    background: var(--color-bg-secondary);
    cursor: not-allowed;
}

/* ===== Swap Button ===== */
.converter__swap {
    display: flex;
    justify-content: center;
    margin: calc(var(--spacing-xxl) + var(--spacing-lg)) 0 var(--spacing-3xl) 0;
    position: relative;
}

.swap-button {
    width: 56px;
    height: 56px;
    border: none;
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary), var(--color-accent));
    color: white;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-normal);
    box-shadow: 0 4px 16px rgba(102, 126, 234, 0.3), 0 2px 8px rgba(0, 0, 0, 0.1);
    position: relative;
    overflow: hidden;
}

.swap-button::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.2), transparent);
    border-radius: 50%;
    transition: all var(--transition-normal);
}

.swap-button:hover {
    transform: rotate(180deg) scale(1.1);
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.4), 0 4px 12px rgba(0, 0, 0, 0.15);
}

.swap-button:hover::before {
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.3), transparent);
}

.swap-button:active {
    transform: rotate(180deg) scale(1.05);
}

/* ===== Conversion Result ===== */
.converter__result {
    margin-top: var(--spacing-xxl);
    padding: var(--spacing-xxl);
    background: linear-gradient(135deg, var(--color-bg-secondary) 0%, var(--color-bg-tertiary) 100%);
    border-radius: var(--radius-xl);
    border: 2px solid var(--color-border);
    text-align: center;
    position: relative;
    overflow: hidden;
    box-shadow: inset 0 1px 3px rgba(0, 0, 0, 0.1), 0 4px 12px rgba(0, 0, 0, 0.05);
}

.converter__result::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(255, 215, 0, 0.05), rgba(220, 20, 60, 0.05));
    pointer-events: none;
}

.result__content {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-text-primary);
    position: relative;
    z-index: 1;
}

.result__text {
    font-family: 'JetBrains Mono', monospace;
    display: block;
    animation: fadeIn var(--transition-normal);
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary), var(--color-accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-size: 1.75rem;
    font-weight: 700;
    letter-spacing: -0.01em;
    margin-top: var(--spacing-lg);
}

.result__text.fade-in {
    animation: resultPulse 0.6s ease-out;
}

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

@keyframes resultPulse {
    0% { transform: scale(0.95); opacity: 0.7; }
    50% { transform: scale(1.02); }
    100% { transform: scale(1); opacity: 1; }
}

@keyframes slideInUp {
    0% {
        opacity: 0;
        transform: translateY(30px);
    }
    100% {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes float {
    0%, 100% {
        transform: translateY(0px);
    }
    50% {
        transform: translateY(-10px);
    }
}

/* ===== Visualization Section ===== */
.visualization {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xl);
}

/* ===== Rates Table ===== */
.rates-table {
    background: var(--color-bg-primary);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-md);
}

.rates-table__title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--color-primary);
    margin-bottom: var(--spacing-lg);
    text-align: center;
}

.rates-table__content {
    overflow-x: auto;
}

.rates-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: var(--spacing-md);
}

.rate-card {
    padding: var(--spacing-md);
    background: var(--color-bg-secondary);
    border-radius: var(--radius-md);
    text-align: center;
    border: 1px solid var(--color-border);
    transition: all var(--transition-fast);
}

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

.rate-card__currency {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-xs);
}

.rate-card__value {
    font-size: 1.125rem;
    font-weight: 700;
    color: var(--color-accent);
}

/* ===== Chart Container ===== */
.chart-container {
    background: var(--color-bg-primary);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-md);
}

.chart__title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--color-primary);
    margin-bottom: var(--spacing-lg);
    text-align: center;
}

.chart__content {
    position: relative;
    height: 300px;
    display: flex;
    align-items: center;
    justify-content: center;
}

#chartCanvas {
    max-width: 100%;
    height: auto;
}

/* ===== History Section ===== */
.history {
    background: var(--color-bg-primary);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-md);
}

.history__title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--color-primary);
    margin-bottom: var(--spacing-lg);
    text-align: center;
}

.history__content {
    max-height: 300px;
    overflow-y: auto;
    margin-bottom: var(--spacing-md);
}

.history__empty {
    text-align: center;
    color: var(--color-text-muted);
    font-style: italic;
    padding: var(--spacing-xl);
}

.history-item {
    padding: var(--spacing-md);
    border-bottom: 1px solid var(--color-border);
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background-color var(--transition-fast);
}

.history-item:hover {
    background: var(--color-bg-secondary);
}

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

.history-item__conversion {
    font-weight: 500;
    color: var(--color-text-primary);
}

.history-item__time {
    font-size: 0.875rem;
    color: var(--color-text-muted);
}

.history__clear {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--color-error);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.history__clear:hover {
    background: #c53030;
    transform: translateY(-1px);
}

.history__clear:disabled {
    background: var(--color-text-light);
    cursor: not-allowed;
    transform: none;
}

/* ===== Fee Calculator Section ===== */
.fee-calculator {
    width: 100%;
    max-width: 800px;
    margin: var(--spacing-2xl) auto 0;
    padding: 0 var(--spacing-lg);
}

.fee-calculator__container {
    background: var(--color-bg-secondary);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl);
    box-shadow: var(--shadow-lg);
    border: 2px solid var(--color-border);
    position: relative;
    overflow: hidden;
}

.fee-calculator__container::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--color-secondary), var(--color-primary));
}

.fee-calculator__title {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--color-text-primary);
    text-align: center;
    margin-bottom: var(--spacing-lg);
    background: linear-gradient(135deg, var(--color-secondary), var(--color-primary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.fee-calculator__info {
    background: var(--color-bg-tertiary);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    border-left: 4px solid var(--color-secondary);
}

.fee-info__text {
    font-size: 0.95rem;
    color: var(--color-text-secondary);
    font-weight: 500;
    text-align: center;
    margin: 0;
}

.fee-calculator__result {
    background: var(--color-bg-primary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    border: 1px solid var(--color-border);
}

.fee-result__content {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.fee-result__item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-sm) 0;
    border-bottom: 1px solid rgba(218, 165, 32, 0.2);
}

.fee-result__item:last-child {
    border-bottom: none;
}

.fee-result__total {
    border-top: 2px solid var(--color-border);
    padding-top: var(--spacing-md);
    margin-top: var(--spacing-sm);
    font-weight: 600;
    font-size: 1.1rem;
}

.fee-result__label {
    color: var(--color-text-secondary);
    font-weight: 500;
}

.fee-result__value {
    color: var(--color-text-primary);
    font-weight: 600;
    font-size: 1.05rem;
}

.fee-result__total .fee-result__value {
    color: var(--color-accent);
    font-size: 1.2rem;
}

/* Fee Reminder Styles */
.fee-reminder {
    background: linear-gradient(135deg, #fff3cd 0%, #ffeaa7 100%);
    border: 1px solid #ffeaa7;
    border-radius: 8px;
    padding: 8px 12px;
    margin: 12px 0 6px 0;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
    text-align: center;
}

.fee-reminder:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
}

.fee-reminder__text {
    color: #856404;
    font-size: 12px;
    font-weight: 500;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
}

.fee-reminder__text::before {
    content: "💰";
    font-size: 14px;
}

#feeReminderAmount {
    color: var(--color-primary);
    font-weight: 700;
}

/* Total with Fee Styles */
.total-with-fee {
    background: linear-gradient(135deg, #d1ecf1 0%, #bee5eb 100%);
    border: 1px solid #bee5eb;
    border-radius: 12px;
    padding: 16px 20px;
    margin: 8px 0 16px 0;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
}

.total-with-fee:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
}

.total-with-fee__text {
    color: #0c5460;
    font-size: 16px;
    font-weight: 700;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

.total-with-fee__text::before {
    content: "💵";
    font-size: 18px;
}

#totalWithFeeAmount {
    color: var(--color-primary);
    font-weight: 700;
    font-size: 1.1rem;
}

/* ===== Footer ===== */
.footer {
    padding: var(--spacing-xl) 0;
    text-align: center;
    border-top: 1px solid var(--color-border);
    margin-top: auto;
}

.footer__text {
    color: var(--color-text-muted);
    font-size: 0.875rem;
}

/* ===== Modal ===== */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--color-bg-overlay);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 10000;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-normal);
}

.modal.show {
    opacity: 1;
    visibility: visible;
}

.modal__content {
    background: var(--color-bg-primary);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
    max-width: 400px;
    width: 90%;
    max-height: 90vh;
    overflow-y: auto;
    transform: scale(0.9);
    transition: transform var(--transition-normal);
}

.modal.show .modal__content {
    transform: scale(1);
}

.modal__header {
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--color-border);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal__title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--color-primary);
}

.modal__close {
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--color-text-muted);
    cursor: pointer;
    padding: 0;
    width: 30px;
    height: 30px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
}

.modal__close:hover {
    background: var(--color-bg-secondary);
    color: var(--color-text-primary);
}

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

.modal__message {
    color: var(--color-text-primary);
    line-height: 1.6;
}

.modal__footer {
    padding: var(--spacing-lg);
    border-top: 1px solid var(--color-border);
    display: flex;
    justify-content: flex-end;
}

.modal__button {
    padding: var(--spacing-sm) var(--spacing-lg);
    background: var(--color-accent);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.modal__button:hover {
    background: #2c5aa0;
}

/* ===== Responsive Design ===== */

/* Tablet (768px - 1023px) */
@media (max-width: 1023px) and (min-width: 768px) {
    .container {
        padding: 0 var(--spacing-lg);
        max-width: 900px;
    }
    
    .main {
        padding: var(--spacing-xl) 0;
        min-height: calc(100vh - 180px);
    }
    
    .header {
        padding: var(--spacing-xl) var(--spacing-lg);
    }
    
    .header__title {
        font-size: 2.25rem;
    }
    
    .header__subtitle {
        font-size: 1.1rem;
    }
    
    .converter {
        padding: 0 var(--spacing-lg);
        max-width: 700px;
    }
    
    .converter__container {
        padding: var(--spacing-2xl);
        border-radius: var(--radius-xl);
    }
    
    .converter__title {
        font-size: 2rem;
        margin-bottom: var(--spacing-2xl);
    }
    
    .input-group__content {
        gap: var(--spacing-lg);
    }
    
    .currency-select,
    .amount-input {
        padding: var(--spacing-lg);
        font-size: 1.1rem;
    }
    
    .swap-button {
        width: 52px;
        height: 52px;
    }
    
    .result__text {
        font-size: 1.6rem;
    }
    
    .fee-calculator {
        max-width: 700px;
    }
    
    .fee-calculator__container {
        padding: var(--spacing-xl);
    }
    
    .converter__explanation {
        padding: var(--spacing-xl);
        max-width: 700px;
        margin-left: auto;
        margin-right: auto;
    }
}

/* Mobile Large (481px - 767px) */
@media (max-width: 767px) {
    .header {
        padding: var(--spacing-xl) var(--spacing-md);
        margin: var(--spacing-md) 0;
    }
    
    .header__title {
        font-size: 1.75rem;
    }
    
    .header__subtitle {
        font-size: 1rem;
    }
    
    .converter,
    .rates-table,
    .chart-container,
    .history {
        padding: var(--spacing-lg);
    }
    
    .input-group__content {
        grid-template-columns: 1fr;
        gap: var(--spacing-sm);
    }
    
    .rates-grid {
        grid-template-columns: repeat(auto-fit, minmax(100px, 1fr));
        gap: var(--spacing-sm);
    }
    
    .chart__content {
        height: 250px;
    }
}

/* Mobile Small (320px - 480px) */
@media (max-width: 480px) {
    :root {
        --spacing-md: 0.75rem;
        --spacing-lg: 1rem;
        --spacing-xl: 1.25rem;
        --spacing-2xl: 1.5rem;
    }
    
    .container {
        padding: var(--spacing-sm);
    }
    
    .header__title {
        font-size: 1.75rem;
        line-height: 1.2;
    }
    
    .header__subtitle {
        font-size: 0.9rem;
        margin-top: var(--spacing-sm);
    }
    
    .converter__container {
        padding: var(--spacing-lg);
        margin: var(--spacing-md) 0;
    }
    
    .converter__title {
        font-size: 1.25rem;
        margin-bottom: var(--spacing-lg);
    }
    
    .input-group__content {
        gap: var(--spacing-md);
    }
    
    .currency-select,
    .amount-input {
        padding: var(--spacing-md);
        font-size: 1rem;
        min-height: 48px; /* Touch-friendly size */
    }
    
    .swap-button {
        width: 48px;
        height: 48px;
        margin: var(--spacing-sm) 0;
    }
    
    .result__text {
        font-size: 1.5rem;
        text-align: center;
    }
    
    .google-rate-explanation {
        padding: var(--spacing-md);
        margin: var(--spacing-md) 0;
    }
    
    .google-rate-explanation h3 {
        font-size: 1rem;
    }
    
    .google-rate-explanation p {
        font-size: 0.875rem;
        line-height: 1.5;
    }
    
    /* Improve touch targets */
    button, .currency-select, .amount-input {
        min-height: 44px;
    }
    
    /* Reduce animations on mobile for better performance */
    .converter__container {
        animation: none;
    }
    
    .converter__container:hover {
        transform: none;
    }
}

/* Ultra-wide screens (1920px+) */
@media (min-width: 1920px) {
    .container {
        max-width: 1400px;
    }
    
    .header__title {
        font-size: 3rem;
    }
    
    .header__subtitle {
        font-size: 1.25rem;
    }
}

/* ===== Utility Classes ===== */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.font-bold { font-weight: 700; }
.font-semibold { font-weight: 600; }
.font-medium { font-weight: 500; }

.text-primary { color: var(--color-text-primary); }
.text-secondary { color: var(--color-text-secondary); }
.text-muted { color: var(--color-text-muted); }
.text-success { color: var(--color-success); }
.text-error { color: var(--color-error); }

.hidden { display: none !important; }
.invisible { visibility: hidden; }
#totalWithFee {
    display: none !important;
}

/* Hide header update time */
.header__update-time {
    display: none !important;
}

/* Style for converter data updated info */
.converter__data-updated {
    margin-top: 10px;
    text-align: center;
}

.data-updated__text {
    font-size: 12px;
    color: #666;
    font-weight: 400;
}

.converter__disclaimer {
    margin-top: 8px;
    text-align: center;
}

.converter__disclaimer .disclaimer-text {
    font-size: 11px;
    color: #888;
    line-height: 1.4;
    margin: 0;
}

/* ===== Animation Classes ===== */
.fade-in {
    animation: fadeIn var(--transition-normal) ease-out;
}

.slide-up {
    animation: slideUp var(--transition-normal) ease-out;
}

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

.pulse {
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.5;
    }
}

/* ===== Print Styles ===== */
@media print {
    .loading-overlay,
    .modal,
    .swap-button,
    .history__clear {
        display: none !important;
    }
    
    body {
        background: white;
    }
    
    .container {
        max-width: none;
        padding: 0;
    }
    
    .main {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .converter,
    .rates-table,
    .chart-container,
    .history {
        box-shadow: none;
        border: 1px solid #ccc;
    }
}

/* ===== Google Rate Explanation Styles ===== */
.converter__explanation {
    margin-top: var(--spacing-xxl);
    padding: var(--spacing-xl);
    background: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
    border-radius: var(--border-radius-lg);
    border: 1px solid var(--color-border);
    position: relative;
    overflow: hidden;
}

.converter__explanation::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
}

.explanation__content {
    position: relative;
    z-index: 1;
}

.explanation__title {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--color-text-primary);
    margin-bottom: var(--spacing-lg);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.explanation__text {
    font-size: 0.95rem;
    line-height: 1.6;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-md);
    text-align: justify;
}

.explanation__text:last-of-type {
    margin-bottom: var(--spacing-lg);
    font-weight: 600;
    color: var(--color-text-primary);
}

.explanation__link {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--color-primary);
    text-decoration: none;
    font-weight: 600;
    font-size: 0.95rem;
    padding: var(--spacing-sm) var(--spacing-md);
    border: 2px solid var(--color-primary);
    border-radius: var(--border-radius-md);
    transition: all var(--transition-fast) ease;
    background: transparent;
}

.explanation__link:hover {
    background: var(--color-primary);
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3);
}

.explanation__link:active {
    transform: translateY(0);
}

/* Responsive adjustments for explanation */
@media (max-width: 768px) {
    .converter__explanation {
        margin-top: var(--spacing-xl);
        padding: var(--spacing-lg);
    }
    
    .explanation__title {
        font-size: 1.1rem;
    }
    
    .explanation__text {
        font-size: 0.9rem;
    }
    
    .explanation__link {
        font-size: 0.9rem;
        padding: var(--spacing-xs) var(--spacing-sm);
    }
}