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

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

/* Container */
.container {
    max-width: 500px;
    margin: 0 auto;
    margin-bottom: 20px;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-radius: 24px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
    padding: 40px;
    border: 1px solid rgba(255, 255, 255, 0.2);
    width: fit-content;
    display: block;
}

/* Header */
.header {
    text-align: center;
    margin-bottom: 30px;
}
.header h1 {
    font-size: 2.5rem;
    font-weight: 600;
    background: linear-gradient(135deg, #667eea, #764ba2);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 8px;
}
.header p {
    font-size: 1.1rem;
    color: #666;
    margin-bottom: 20px;
}
.header span {
    font-size: 0.9rem;
    color: #666;
    font-weight: 300;
}

/* Description */
.description {
    text-align: center;
    margin-bottom: 40px;
    color: #4a5568;
}
.description h2 {
    font-size: 1.5rem;
    margin-top: 15px;
    margin-bottom: 15px;
    color: #2d3748;
}

/* Donate Section */
.donate-options {
    display: grid;
    gap: 20px;
    margin-bottom: 30px;
    align-items: start;
}
.donate-card {
    background: white;
    border-radius: 16px;
    padding: 25px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    border: 2px solid transparent;
}
.donate-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
    border-color: #667eea;
}
.donate-card h3 {
    font-size: 1.3rem;
    margin-bottom: 10px;
    color: #2d3748;
    display: flex;
    align-items: center;
    gap: 10px;
}
.donate-card p {
    color: #666;
    margin-bottom: 15px;
}
.donate-input {
    display: flex;
    gap: 10px;
    margin-bottom: 15px;
}
.amount-input {
    flex: 1;
    padding: 12px 16px;
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.2s ease;
}
.amount-input:focus {
    outline: none;
    border-color: #667eea;
}
.currency-select {
    padding: 12px 16px;
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    font-size: 1rem;
    background: white;
    cursor: pointer;
}
.quick-amounts {
    display: flex;
    gap: 8px;
    margin-bottom: 15px;
    flex-wrap: wrap;
    justify-content: flex-start;
}
.quick-amount {
    padding: 8px 16px;
    border: 2px solid #e2e8f0;
    border-radius: 20px;
    background: white;
    cursor: pointer;
    transition: all 0.2s ease;
    font-size: 0.9rem;
}
.quick-amount:hover {
    border-color: #667eea;
    background: #f8f9ff;
}

/* Donate Buttons */
.donate-btn {
    width: 100%;
    padding: 15px;
    border: none;
    border-radius: 12px;
    aspect-ratio: auto;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    color: white;
}
.paypal-btn {
    background: linear-gradient(135deg, #0070ba, #003087);
}
.crypto-btn {
    background: linear-gradient(135deg, #f7931a, #ff6b35);
}
.coffee-btn {
    background: linear-gradient(135deg, #ff6b6b, #ee5a52);
    padding: 8px 16px; /* Less tall */
}
.donate-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.2);
}

/* Crypto Address */
.crypto-address {
    background: #f8f9fa;
    padding: 15px;
    border-radius: 8px;
    font-family: 'Courier New', monospace;
    font-size: 0.9rem;
    word-break: break-all;
    margin-top: 10px;
    border: 1px solid #e2e8f0;
}

/* Copy Button */
.copy-btn {
    background: #667eea;
    color: white;
    border: none;
    padding: 8px 12px;
    border-radius: 6px;
    aspect-ratio: auto;
    cursor: pointer;
    font-size: 0.8rem;
    margin-top: 8px;
    transition: background 0.2s ease;
}
.copy-btn:hover {
    background: #5a67d8;
}

/* Back Link */
.back-link {
    text-align: center;
    margin-top: 30px;
}
.back-link a {
    color: #667eea;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s ease;
}
.back-link a:hover {
    color: #5a67d8;
}

/* Icon */
.icon {
    font-size: 1.5rem;
}

/* Calculator */
.calculator {
    background: rgba(255, 255, 255, 0.95);
    margin: auto;
    margin-bottom: 20px;
    backdrop-filter: blur(10px);
    border-radius: 24px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
    padding: 30px;
    max-width: 500px;
    width: 100%;
    border: 1px solid rgba(255, 255, 255, 0.2);
}
.display {
    background: #1a1a1a;
    color: white;
    font-size: 2.5rem;
    font-weight: 300;
    text-align: right;
    padding: 20px;
    border-radius: 12px;
    margin-bottom: 20px;
    min-height: 80px;
    display: flex;
    align-items: center;
    justify-content: flex-end;
    word-wrap: break-word;
    overflow-wrap: break-word;
}
.buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-template-rows: repeat(5, 1fr);
    gap: 12px;
}
button {
    aspect-ratio: 1;
    border: none;
    border-radius: 12px;
    font-size: 2rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}
button:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
}
button:active {
    transform: translateY(0);
}
.btn-number {
    background: linear-gradient(135deg, #f8f9fa, #e9ecef);
    color: #2d3748;
}
.btn-operator {
    background: linear-gradient(135deg, #ff6b6b, #ee5a52);
    color: white;
}
.btn-clear {
    background: linear-gradient(135deg, #ffd93d, #ff8c00);
    color: white;
}
.btn-equals {
    background: linear-gradient(135deg, #4ecdc4, #44a08d);
    color: white;
}

/* Donate Button Section */
.donate-button {
    margin-top: 20px;
    width: 100%;
}
.donate-button button {
    width: 100%;
    padding: 12px 0;
    font-size: 16px;
    font-weight: 500;
    background-color: #ffc107;
    color: #000;
    border: none;
    border-radius: 12px;
    box-shadow: none;
    cursor: pointer;
    transition: background-color 0.2s ease;
}
.donate-button button:hover {
    background-color: #e0a800;
}

/* Responsive */
@media (max-width: 480px) {
    .container {
        padding: 25px;
    }
    .header h1 {
        font-size: 2rem;
    }
    .donate-input {
        flex-direction: column;
    }
    .quick-amounts {
        justify-content: center;
    }
    .calculator {
        padding: 20px;
    }
    .display {
        font-size: 2rem;
    }
    button {
        font-size: 1.1rem;
    }
}