:root {
    --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --converter-card-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
    --result-box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

body {
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    min-height: 100vh;
    padding: 20px 0;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

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

.converter-card {
    border-radius: 15px;
    box-shadow: var(--converter-card-shadow);
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border: none;
}

.converter-header {
    background: var(--primary-gradient);
    color: white;
    border-top-left-radius: 15px;
    border-top-right-radius: 15px;
}

.nav-tabs .nav-link {
    font-weight: 600;
    color: #6c757d;
    border: none;
}

.nav-tabs .nav-link.active {
    color: #667eea;
    border: none;
    border-bottom: 3px solid #667eea;
    font-weight: 700;
}

.converter-tab-pane {
    display: none;
}

.converter-tab-pane.active {
    display: block;
    animation: fadeIn 0.3s ease-in;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.converter-input-group {
    margin-bottom: 20px;
}

.result-box {
    min-height: 80px;
    font-size: 1.2rem;
    transition: all 0.3s ease;
    background: #f8f9fa;
    border-radius: 10px;
    padding: 15px;
    margin: 20px 0;
    box-shadow: var(--result-box-shadow);
}

.converter-btn {
    transition: all 0.2s;
}

.converter-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.converter-icon {
    font-size: 1.5rem;
    margin-right: 10px;
}

.footer {
    text-align: center;
    padding: 20px;
    color: #6c757d;
    font-size: 0.9rem;
}

.converter-title {
    font-weight: 700;
    margin-bottom: 0;
}

.converter-subtitle {
    opacity: 0.9;
    font-size: 0.9rem;
}

.form-control, .form-select {
    border-radius: 10px;
    padding: 12px 15px;
    border: 1px solid #e1e5eb;
}

.form-control:focus, .form-select:focus {
    border-color: #667eea;
    box-shadow: 0 0 0 0.25rem rgba(102, 126, 234, 0.15);
}

.btn-primary {
    background: var(--primary-gradient);
    border: none;
    border-radius: 10px;
    padding: 12px 20px;
    font-weight: 600;
}

.btn-primary:hover {
    background: linear-gradient(135deg, #5a6fd8 0%, #6a4190 100%);
}

.theme-toggle {
    position: absolute;
    top: 20px;
    right: 20px;
    background: rgba(255, 255, 255, 0.2);
    border: none;
    border-radius: 50%;
    width: 40px;
    height: 40px;
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

/* Dark mode styles */
body.dark-mode {
    background: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
    color: #e1e5eb;
}

body.dark-mode .converter-card {
    background: rgba(30, 30, 46, 0.95);
    color: #e1e5eb;
}

body.dark-mode .form-control, 
body.dark-mode .form-select {
    background: rgba(50, 50, 70, 0.8);
    border: 1px solid #44476a;
    color: #e1e5eb;
}

body.dark-mode .form-control:focus, 
body.dark-mode .form-select:focus {
    border-color: #667eea;
    box-shadow: 0 0 0 0.25rem rgba(102, 126, 234, 0.25);
}

body.dark-mode .result-box {
    background: rgba(50, 50, 70, 0.5);
    color: #e1e5eb;
}

body.dark-mode .nav-tabs .nav-link {
    color: #a0a7c5;
}

body.dark-mode .nav-tabs .nav-link.active {
    color: #667eea;
}

body.dark-mode .text-muted {
    color: #a0a7c5 !important;
}