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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: #333;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
}

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

/* Header Styles */
.header {
    text-align: center;
    margin-bottom: 2rem;
    color: white;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
    margin-bottom: 10px;
}

.logo i {
    font-size: 2.5rem;
    color: #fff;
}

.logo h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin: 0;
}

.tagline {
    font-size: 1.1rem;
    opacity: 0.9;
    font-weight: 300;
}

/* Category Navigation */
.category-nav {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 10px;
    margin-bottom: 2rem;
    padding: 20px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 20px;
    backdrop-filter: blur(10px);
}

.category-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    padding: 15px 10px;
    background: rgba(255, 255, 255, 0.1);
    border: 2px solid transparent;
    border-radius: 15px;
    color: white;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 0.9rem;
    font-weight: 500;
}

.category-btn:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: translateY(-2px);
}

.category-btn.active {
    background: rgba(255, 255, 255, 0.25);
    border-color: rgba(255, 255, 255, 0.3);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
}

.category-btn i {
    font-size: 1.5rem;
}

/* Converter Card */
.converter {
    margin-bottom: 2rem;
}

.converter-card {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 25px;
    padding: 30px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.1);
    backdrop-filter: blur(10px);
}

.conversion-row {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    gap: 20px;
    align-items: end;
    margin-bottom: 30px;
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.input-group label {
    font-weight: 600;
    color: #555;
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.input-group input,
.input-group select {
    padding: 15px;
    border: 2px solid #e1e5e9;
    border-radius: 12px;
    font-size: 1.1rem;
    transition: all 0.3s ease;
    background: white;
}

.input-group input:focus,
.input-group select:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.input-group input[readonly] {
    background: #f8f9fa;
    color: #28a745;
    font-weight: 600;
}

.swap-btn {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: linear-gradient(135deg, #667eea, #764ba2);
    border: none;
    color: white;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    align-self: center;
}

.swap-btn:hover {
    transform: rotate(180deg) scale(1.1);
    box-shadow: 0 8px 25px rgba(102, 126, 234, 0.3);
}

/* Quick Convert Section */
.quick-convert {
    border-top: 2px solid #e1e5e9;
    padding-top: 25px;
}

.quick-convert h3 {
    color: #555;
    margin-bottom: 15px;
    font-weight: 600;
}

.quick-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 15px;
}

.quick-item {
    padding: 15px;
    background: #f8f9fa;
    border-radius: 10px;
    border-left: 4px solid #667eea;
    transition: all 0.3s ease;
    cursor: pointer;
}

.quick-item:hover {
    background: #e9ecef;
    transform: translateX(5px);
}

.quick-from {
    font-weight: 600;
    color: #333;
    margin-bottom: 5px;
}

.quick-to {
    color: #28a745;
    font-weight: 500;
}

/* Footer */
.footer {
    text-align: center;
    color: rgba(255, 255, 255, 0.8);
    font-size: 0.9rem;
    margin-top: 2rem;
}

.precision-note {
    font-size: 0.8rem;
    opacity: 0.7;
    margin-top: 5px;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 15px;
    }
    
    .logo h1 {
        font-size: 2rem;
    }
    
    .category-nav {
        grid-template-columns: repeat(4, 1fr);
        gap: 8px;
        padding: 15px;
    }
    
    .category-btn {
        padding: 12px 8px;
        font-size: 0.8rem;
    }
    
    .category-btn i {
        font-size: 1.2rem;
    }
    
    .category-btn span {
        display: none;
    }
    
    .conversion-row {
        grid-template-columns: 1fr;
        gap: 15px;
    }
    
    .swap-btn {
        justify-self: center;
        transform: rotate(90deg);
    }
    
    .converter-card {
        padding: 20px;
    }
    
    .quick-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .category-nav {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .input-group input,
    .input-group select {
        padding: 12px;
        font-size: 1rem;
    }
}

/* Animation Classes */
.fade-in {
    animation: fadeIn 0.3s ease-in;
}

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

.pulse {
    animation: pulse 0.3s ease-in-out;
}

@keyframes pulse {
    0% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.05);
    }
    100% {
        transform: scale(1);
    }
}

/* Loading State */
.loading {
    position: relative;
    overflow: hidden;
}

.loading::after {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.4), transparent);
    animation: loading 1.5s infinite;
}

@keyframes loading {
    0% {
        left: -100%;
    }
    100% {
        left: 100%;
    }
}