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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: #333;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    background: white;
    border-radius: 20px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    overflow: hidden;
}

header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 40px 30px;
    text-align: center;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
}

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

main {
    padding: 40px 30px;
}

.calculator-section, .results-section {
    margin-bottom: 40px;
}

h2 {
    color: #667eea;
    font-size: 1.8rem;
    margin-bottom: 25px;
    padding-bottom: 10px;
    border-bottom: 3px solid #667eea;
}

h3 {
    color: #764ba2;
    font-size: 1.4rem;
    margin-bottom: 15px;
}

.form-group {
    margin-bottom: 20px;
}

label {
    display: block;
    font-weight: 600;
    margin-bottom: 8px;
    color: #555;
}

input[type="number"],
select {
    width: 100%;
    padding: 12px 15px;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    font-size: 1rem;
    transition: all 0.3s ease;
}

input[type="number"]:focus,
select:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

input[type="number"]::placeholder {
    color: #aaa;
}

.btn-primary {
    width: 100%;
    padding: 15px 30px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-secondary {
    display: inline-block;
    padding: 10px 20px;
    margin: 5px;
    background: white;
    color: #667eea;
    border: 2px solid #667eea;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
}

.btn-secondary:hover {
    background: #667eea;
    color: white;
}

.loading {
    text-align: center;
    padding: 30px;
}

.spinner {
    border: 4px solid #f3f3f3;
    border-top: 4px solid #667eea;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    animation: spin 1s linear infinite;
    margin: 0 auto 15px;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.results-content {
    background: #f8f9fa;
    padding: 25px;
    border-radius: 12px;
    margin-top: 20px;
}

.result-card {
    background: white;
    padding: 20px;
    border-radius: 10px;
    margin-bottom: 15px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.result-card h3 {
    margin-bottom: 15px;
    color: #667eea;
}

.result-item {
    display: flex;
    justify-content: space-between;
    padding: 10px 0;
    border-bottom: 1px solid #e0e0e0;
}

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

.result-label {
    font-weight: 600;
    color: #555;
}

.result-value {
    font-weight: 700;
    color: #333;
}

.comparison-summary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 20px;
    border-radius: 10px;
    margin-top: 20px;
    text-align: center;
}

.comparison-summary h3 {
    color: white;
    margin-bottom: 10px;
}

.error-message {
    background: #fee;
    color: #c33;
    padding: 15px;
    border-radius: 8px;
    border-left: 4px solid #c33;
    margin-top: 20px;
}

footer {
    background: #f8f9fa;
    padding: 40px 30px;
}

.coffee-section, .collaboration-section {
    text-align: center;
    margin-bottom: 30px;
}

.coffee-section p, .collaboration-section p {
    margin-bottom: 15px;
    color: #666;
}

.contact-links {
    margin-top: 15px;
}

@media (max-width: 768px) {
    body {
        padding: 10px;
    }

    header h1 {
        font-size: 2rem;
    }

    .container {
        border-radius: 15px;
    }

    main, footer {
        padding: 25px 20px;
    }

    h2 {
        font-size: 1.5rem;
    }

    .btn-secondary {
        display: block;
        margin: 10px 0;
    }
}