/* CSS Custom Properties - Light Theme (default) */
:root {
    --primary: #2563eb;
    --primary-hover: #1d4ed8;
    --primary-light: #dbeafe;
    --secondary: #059669;
    --secondary-hover: #047857;
    --background: #f8fafc;
    --surface: #ffffff;
    --surface-hover: #f1f5f9;
    --surface-elevated: #ffffff;
    --border: #e2e8f0;
    --border-focus: #2563eb;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #94a3b8;
    --success: #059669;
    --error: #dc2626;
    --warning: #d97706;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
    --radius-sm: 6px;
    --radius: 10px;
    --radius-lg: 16px;
    --transition: 150ms ease;
    --transition-slow: 300ms ease;
    --flag-shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
}

/* Dark Theme */
[data-theme="dark"] {
    --primary: #3b82f6;
    --primary-hover: #60a5fa;
    --primary-light: #1e3a5f;
    --secondary: #10b981;
    --secondary-hover: #34d399;
    --background: #0f172a;
    --surface: #1e293b;
    --surface-hover: #334155;
    --surface-elevated: #1e293b;
    --border: #334155;
    --border-focus: #3b82f6;
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-muted: #64748b;
    --success: #10b981;
    --error: #ef4444;
    --warning: #f59e0b;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.3);
    --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.4), 0 2px 4px -2px rgb(0 0 0 / 0.3);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.4), 0 4px 6px -4px rgb(0 0 0 / 0.3);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.5), 0 8px 10px -6px rgb(0 0 0 / 0.4);
    --flag-shadow: 0 1px 3px 0 rgb(0 0 0 / 0.3), 0 1px 2px -1px rgb(0 0 0 / 0.2);
}

/* Reset & Base */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    transition: background-color var(--transition-slow), color var(--transition-slow);
}

/* Hide number input spinners (for any type="number" that might exist) */
input::-webkit-outer-spin-button,
input::-webkit-inner-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

input[type="number"] {
    -moz-appearance: textfield;
}

/* App Container */
.app-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    max-width: 640px;
    width: 100%;
    margin: 0 auto;
    padding: 24px 16px;
}

/* Header */
.header {
    margin-bottom: 24px;
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    flex-wrap: wrap;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    color: var(--primary);
    font-weight: 700;
    font-size: 1.25rem;
}

.logo-icon {
    flex-shrink: 0;
    transition: transform var(--transition);
}

.logo:hover .logo-icon {
    transform: rotate(15deg);
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 12px;
}

.rate-badge {
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 2px;
    padding: 8px 12px;
    background: var(--primary-light);
    border-radius: var(--radius);
    min-width: 120px;
    border: 1px solid var(--border);
}

.rate-label {
    font-size: 0.625rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--primary);
}

.rate-value {
    font-size: 0.875rem;
    font-weight: 700;
    font-variant-numeric: tabular-nums;
    color: var(--text-primary);
}

/* Theme Toggle */
.theme-toggle {
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition);
    position: relative;
}

.theme-toggle:hover {
    background: var(--surface-hover);
    border-color: var(--primary);
    color: var(--primary);
}

.theme-toggle:focus {
    outline: none;
    box-shadow: 0 0 0 3px var(--primary-light);
}

.theme-toggle .icon-sun {
    display: none;
}

.theme-toggle .icon-moon {
    display: block;
}

[data-theme="light"] .theme-toggle .icon-sun {
    display: block;
}

[data-theme="light"] .theme-toggle .icon-moon {
    display: none;
}

/* Main */
.main {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 24px;
    width: 100%;
}

/* Converter Card */
.converter-card {
    background: var(--surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border);
    overflow: hidden;
    transition: background-color var(--transition-slow), border-color var(--transition-slow), box-shadow var(--transition-slow);
}

.converter-header {
    padding: 24px 24px 16px;
    text-align: center;
    border-bottom: 1px solid var(--border);
}

.converter-header h1 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 4px;
}

.subtitle {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.converter-body {
    padding: 24px;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

/* Field Groups */
.field-group {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.field-label {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-secondary);
}

.field-label .flag-wrapper {
    flex-shrink: 0;
}

.currency-name {
    font-weight: 500;
    color: var(--text-primary);
}

.flag-wrapper {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 28px;
    height: 20px;
    border-radius: 3px;
    overflow: hidden;
    box-shadow: var(--flag-shadow);
    flex-shrink: 0;
}

.currency-flag {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

.input-wrapper {
    position: relative;
    display: flex;
    align-items: center;
}

.currency-symbol {
    position: absolute;
    left: 14px;
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-muted);
    pointer-events: none;
    z-index: 1;
    transition: color var(--transition);
}

.result-wrapper .currency-symbol {
    color: var(--secondary);
}

.amount-input {
    width: 100%;
    padding: 14px 16px 14px 42px;
    font-size: 1.25rem;
    font-weight: 500;
    font-family: inherit;
    color: var(--text-primary);
    background: var(--background);
    border: 2px solid var(--border);
    border-radius: var(--radius);
    outline: none;
    transition: border-color var(--transition), box-shadow var(--transition), background-color var(--transition), color var(--transition);
}

.amount-input::placeholder {
    color: var(--text-muted);
    font-weight: 400;
}

.amount-input:hover {
    border-color: #cbd5e1;
    background: var(--surface);
}

[data-theme="dark"] .amount-input:hover {
    border-color: #475569;
}

.amount-input:focus {
    border-color: var(--border-focus);
    box-shadow: 0 0 0 3px var(--primary-light);
    background: var(--surface);
}

.result-input {
    background: var(--primary-light);
    border-color: var(--primary);
    color: var(--primary);
    font-weight: 700;
}

.result-input:focus {
    box-shadow: 0 0 0 3px var(--primary-light);
}

/* Swap Button */
.swap-btn {
    align-self: center;
    width: 56px;
    height: 56px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--background);
    border: 2px solid var(--border);
    border-radius: 50%;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition);
    flex-shrink: 0;
    margin: 4px 0;
}

.swap-btn:hover {
    background: var(--surface);
    border-color: var(--primary);
    color: var(--primary);
    transform: rotate(180deg);
    box-shadow: var(--shadow);
}

.swap-btn:active {
    transform: rotate(180deg) scale(0.95);
}

.swap-btn:focus {
    outline: none;
    box-shadow: 0 0 0 3px var(--primary-light);
}

/* Converter Footer */
.converter-footer {
    padding: 16px 24px 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 12px;
    border-top: 1px solid var(--border);
    background: var(--background).
}

.rate-info {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 12px;
    background: var(--surface);
    border-radius: var(--radius);
    border: 1px solid var(--border);
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary).
}

.info-icon {
    font-size: 0.75rem;
    color: var(--primary);
    background: var(--primary-light);
    width: 20px;
    height: 20px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center.
    flex-shrink: 0.
}

.last-updated {
    font-size: 0.75rem;
    color: var(--text-muted).
}

.last-updated span {
    font-variant-numeric: tabular-nums;
    color: var(--text-secondary).
}

/* Footer */
.footer {
    margin-top: auto;
    padding: 16px 16px 8px;
    text-align: center.
    color: var(--text-muted).
    font-size: 0.75rem.
}

.footer p {
    margin-bottom: 4px.
}

.footer a {
    color: var(--primary).
    text-decoration: none.
    font-weight: 500.
}

.footer a:hover {
    text-decoration: underline.
}

.disclaimer {
    color: var(--text-muted) !important.
}

/* Responsive */
@media (max-width: 520px) {
    .app-container {
        padding: 16px 12px.
    }

    .header-content {
        flex-direction: column.
        align-items: flex-start.
    }

    .header-actions {
        width: 100%.
        justify-content: space-between.
    }

    .rate-badge {
        align-items: flex-start.
        width: 100%.
    }

    .converter-header {
        padding: 20px 20px 12px.
    }

    .converter-body {
        padding: 20px.
        gap: 12px.
    }

    .converter-footer {
        padding: 16px 20px 20px.
        flex-direction: column.
        align-items: flex-start.
    }

    .swap-btn {
        width: 48px.
        height: 48px.
        margin: 0.
    }

    .swap-btn:hover {
        transform: none.
    }

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

    .amount-input {
        font-size: 1.125rem.
        padding: 12px 14px 12px 40px.
    }

    .flag-wrapper {
        width: 24px.
        height: 18px.
    }
}

@media (max-width: 380px) {
    .converter-header h1 {
        font-size: 1.25rem.
    }
}

/* Reduced Motion */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important.
        animation-iteration-count: 1 !important.
        transition-duration: 0.01ms !important.
    }
}

/* Focus Visible for Keyboard Navigation */
:focus:not(:focus-visible) {
    outline: none.
    box-shadow: none.
}

:focus-visible {
    outline: none.
    box-shadow: 0 0 0 3px var(--primary-light).
}