* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #007BFF;
    --primary-dark: #0056b3;
    --secondary-color: #6c757d;
    --success-color: #28a745;
    --danger-color: #dc3545;
    --warning-color: #ffc107;
    --light-bg: #f8f9fa;
    --white: #ffffff;
    --text-dark: #212529;
    --text-light: #6c757d;
    --border-color: #dee2e6;
    --shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    --shadow-hover: 0 4px 20px rgba(0, 0, 0, 0.15);
}

body {
    font-family: 'Poppins', sans-serif;
    background-color: var(--light-bg);
    color: var(--text-dark);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

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

/* Header */
.header {
    background: var(--white);
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.logo a {
    display: flex;
    align-items: center;
    text-decoration: none;
    color: var(--text-dark);
    font-weight: 600;
    font-size: 1.2rem;
}

.logo-icon {
    font-size: 1.8rem;
    margin-right: 0.5rem;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-dark);
    font-weight: 500;
    transition: color 0.3s;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--primary-color);
}

.language-selector select {
    padding: 0.5rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    background: var(--white);
    color: var(--text-dark);
    font-family: 'Poppins', sans-serif;
    font-weight: 500;
    cursor: pointer;
    transition: border-color 0.3s;
}

.language-selector select:hover {
    border-color: var(--primary-color);
}

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
}

.mobile-menu-toggle span {
    width: 25px;
    height: 3px;
    background: var(--text-dark);
    transition: 0.3s;
}

/* Main Content */
.main-content {
    flex: 1;
    padding: 3rem 0;
}

/* Card */
.card {
    background: var(--white);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: var(--shadow);
    margin-bottom: 2rem;
    transition: box-shadow 0.3s;
}

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

.card-title {
    font-size: 1.8rem;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 0.5rem;
}

.card-subtitle {
    color: var(--text-light);
    margin-bottom: 2rem;
}

/* Form */
.form-group {
    margin-bottom: 1.5rem;
}

.form-label {
    display: block;
    font-weight: 500;
    margin-bottom: 0.5rem;
    color: var(--text-dark);
}

.form-control {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-family: 'Poppins', sans-serif;
    font-size: 1rem;
    transition: border-color 0.3s;
}

.form-control:focus {
    outline: none;
    border-color: var(--primary-color);
}

.form-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
}

/* Button */
.btn {
    padding: 0.75rem 2rem;
    border: none;
    border-radius: 8px;
    font-family: 'Poppins', sans-serif;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s;
    text-decoration: none;
    display: inline-block;
    text-align: center;
}

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

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
}

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

.btn-secondary:hover {
    background: #5a6268;
}

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

.btn-block {
    width: 100%;
}

.btn-group {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

/* Result Box */
.result-box {
    background: linear-gradient(135deg, var(--primary-color), #0056b3);
    color: var(--white);
    padding: 2rem;
    border-radius: 12px;
    margin: 2rem 0;
    text-align: center;
}

.result-amount {
    font-size: 2.5rem;
    font-weight: 700;
    margin: 1rem 0;
}

.result-rate {
    font-size: 1.1rem;
    opacity: 0.9;
    margin: 0.5rem 0;
}

.result-date {
    font-size: 0.9rem;
    opacity: 0.8;
}

/* History */
.history-list {
    list-style: none;
}

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

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

.history-conversion {
    font-weight: 500;
}

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

/* Ad Container */
.ad-container {
    margin: 2rem 0;
    text-align: center;
}

.ad-header {
    margin-bottom: 2rem;
}

.ad-content {
    margin: 2rem 0;
}

.ad-footer {
    margin-top: 2rem;
}

/* Footer */
.footer {
    background: var(--text-dark);
    color: var(--white);
    padding: 3rem 0 1rem;
    margin-top: auto;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h3,
.footer-section h4 {
    margin-bottom: 1rem;
}

.footer-section ul {
    list-style: none;
}

.footer-section ul li {
    margin-bottom: 0.5rem;
}

.footer-section a {
    color: var(--white);
    text-decoration: none;
    opacity: 0.8;
    transition: opacity 0.3s;
}

.footer-section a:hover {
    opacity: 1;
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

/* Alert */
.alert {
    padding: 1rem;
    border-radius: 8px;
    margin-bottom: 1rem;
}

.alert-success {
    background: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.alert-error {
    background: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

.alert-info {
    background: #d1ecf1;
    color: #0c5460;
    border: 1px solid #bee5eb;
}

/* Table */
.table {
    width: 100%;
    border-collapse: collapse;
    margin: 1rem 0;
}

.table th,
.table td {
    padding: 0.75rem;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.table th {
    font-weight: 600;
    background: var(--light-bg);
}

/* Responsive */
@media (max-width: 768px) {
    .mobile-menu-toggle {
        display: flex;
    }
    
    .nav-menu {
        position: fixed;
        top: 70px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 70px);
        background: var(--white);
        flex-direction: column;
        padding: 2rem;
        transition: left 0.3s;
        box-shadow: var(--shadow);
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .nav-links {
        flex-direction: column;
        width: 100%;
    }
    
    .nav-links li {
        width: 100%;
        text-align: center;
    }
    
    .result-amount {
        font-size: 2rem;
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .btn-group {
        flex-direction: column;
    }
    
    .btn-group .btn {
        width: 100%;
    }
}

/* Loading */
.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: var(--white);
    animation: spin 1s ease-in-out infinite;
}

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

/* Utilities */
.text-center {
    text-align: center;
}

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }

.text-muted {
    color: var(--text-light);
}

.text-primary {
    color: var(--primary-color);
}