:root {
    --primary: #007AFF;
    --primary-hover: #0056b3;
    --success: #34C759;
    --error: #FF3B30;
    --background: #f5f7fa;
    --text: #1c1c1e;
    --text-secondary: #6c757d;
    --shadow-sm: 0 2px 8px rgba(0,0,0,0.08);
    --shadow-md: 0 4px 16px rgba(0,0,0,0.12);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

body {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    margin: 0;
    padding: 0;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
    background: var(--background);
    color: var(--text);
    line-height: 1.5;
}

/* Navigation */
.navigation {
    width: 100%;
    background: white;
    border-bottom: 1px solid #e0e0e0;
    position: fixed;
    top: 0;
    z-index: 1000;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem 2rem;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
    color: var(--text);
    font-weight: 600;
    font-size: 1.1rem;
}

.nav-links {
    display: flex;
    gap: 1rem;
}

.nav-link {
    padding: 0.5rem 1rem;
    text-decoration: none;
    color: var(--text-secondary);
    border-radius: 8px;
    transition: var(--transition);
}

.nav-link:hover {
    background: #f8f9fa;
    color: var(--text);
}

.nav-link.active {
    background: var(--primary);
    color: white;
}

.container {
    width: 100%;
    max-width: 600px;
    text-align: center;
    background: white;
    padding: 2.5rem;
    margin: 100px 20px 20px 20px;
    border-radius: 16px;
    box-shadow: var(--shadow-md);
    transition: var(--transition);
}

h1 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
    color: var(--text);
}

p {
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

/* Form styles */
.input-wrapper {
    display: flex;
    gap: 12px;
    margin: 24px 0;
}

.input-field {
    flex: 1;
    padding: 14px 16px;
    border: 2px solid #e1e1e1;
    border-radius: 10px;
    font-size: 16px;
    transition: var(--transition);
}

.input-field:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(0,122,255,0.1);
    outline: none;
}

.convert-button {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 14px 28px;
    background: var(--primary);
    color: white;
    border: none;
    border-radius: 10px;
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition), border-radius 0.3s ease;
}

.convert-button:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-sm);
    border-radius: 25px;
}

/* Result styles */
.success {
    margin-top: 24px;
    padding: 16px;
    background: rgba(52,199,89,0.1);
    border-radius: 10px;
    color: var(--success);
    animation: fadeIn 0.3s ease;
}

.error {
    margin-top: 24px;
    padding: 16px;
    background: rgba(255,59,48,0.1);
    border-radius: 10px;
    color: var(--error);
    animation: fadeIn 0.3s ease;
}

/* Example section */
.example {
    margin-top: 20px;
    padding: 12px;
    background: rgba(0,122,255,0.05);
    border-radius: 8px;
    color: var(--text-secondary);
}

.example-link {
    color: var(--primary);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
}

.example-link:hover {
    opacity: 0.8;
}

/* Info message */
.info-message {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    margin-top: 24px;
    padding: 16px;
    background: rgba(0,0,0,0.03);
    border-radius: 10px;
    color: var(--text-secondary);
}

/* OS Warning */
.os-warning {
    position: fixed;
    bottom: 24px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 16px 24px;
    background: white;
    border-radius: 12px;
    box-shadow: var(--shadow-md);
    animation: slideUp 0.3s ease;
}

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

@keyframes slideUp {
    from { transform: translate(-50%, 100%); opacity: 0; }
    to { transform: translate(-50%, 0); opacity: 1; }
}

/* Add hover effects for interactive elements */
.result-link {
    color: var(--primary);
    text-decoration: none;
    transition: var(--transition);
}

.result-link:hover {
    opacity: 0.8;
}

/* Mobile responsive styles */
@media (max-width: 768px) {
    .nav-container {
        padding: 1rem;
    }
    
    .nav-logo {
        font-size: 1rem;
    }
    
    .nav-links {
        gap: 0.5rem;
    }
    
    .nav-link {
        padding: 0.4rem 0.8rem;
        font-size: 0.9rem;
    }
    
    .container {
        margin: 80px 10px 10px 10px;
        padding: 1.5rem;
    }
    
    h1 {
        font-size: 1.5rem;
    }
}

/* Better table styles for bulk converter */
.csv-table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
    margin-top: 24px;
    background: white;
    border-radius: 10px;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}

.csv-table td {
    padding: 16px;
    border-bottom: 1px solid rgba(0,0,0,0.05);
}

.csv-table tr:last-child td {
    border-bottom: none;
}

/* Footer styles */
.footer {
    margin-top: 40px;
    padding: 16px;
    color: var(--text-secondary);
    font-size: 0.9rem;
    opacity: 0.8;
    transition: var(--transition);
}

.footer a {
    color: var(--primary);
    text-decoration: none;
    transition: var(--transition);
}

.footer a:hover {
    opacity: 0.8;
}

.footer-heart {
    color: var(--error);
    display: inline-block;
    transform: scale(1);
    animation: heartbeat 1.5s infinite;
}

@keyframes heartbeat {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.1); }
}