* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Roboto', sans-serif;
}

body {
    background-color: #f5f5f5;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
}

.container {
    width: 100%;
    max-width: 500px;
    position: relative;
}

.tip-screen, .content-screen, .custom-tip-screen {
    background-color: white;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    padding: 30px;
    width: 100%;
    transition: all 0.3s ease;
}

.header {
    text-align: center;
    margin-bottom: 30px;
}

.logo {
    font-size: 40px;
    margin-bottom: 15px;
}

.logo.large {
    font-size: 60px;
    margin-bottom: 20px;
}

h1 {
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 10px;
    color: #333;
}

.subheader {
    font-size: 18px;
    color: #666;
}

.tip-options {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 15px;
    margin-bottom: 20px;
}

.tip-button {
    background-color: #f8f8f8;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    padding: 20px 15px;
    font-size: 20px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    position: relative;
}

.tip-button:hover {
    border-color: #2196F3;
    background-color: #f0f7ff;
}

.tip-button.selected {
    border-color: #2196F3;
    background-color: #e3f2fd;
}

.amount {
    display: block;
    font-size: 16px;
    margin-top: 5px;
    color: #666;
}

.label {
    position: absolute;
    top: 5px;
    right: 5px;
    font-size: 12px;
    background-color: #e3f2fd;
    color: #2196F3;
    padding: 2px 6px;
    border-radius: 10px;
}

.custom-option {
    margin-bottom: 20px;
}

.custom-option .tip-button {
    width: 100%;
}

.no-tip-option {
    margin-bottom: 20px;
}

.no-tip-button {
    width: 100%;
    padding: 15px;
    background-color: #f8f8f8;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    font-size: 16px;
    color: #666;
    cursor: pointer;
    transition: all 0.2s ease;
}

.no-tip-button:hover {
    background-color: #f0f0f0;
}

.footer {
    text-align: center;
    color: #666;
    font-size: 14px;
    border-top: 1px solid #eee;
    padding-top: 20px;
}

.small-text {
    font-size: 12px;
    color: #999;
    margin-top: 5px;
}

.hidden {
    display: none;
}

.content-screen {
    text-align: center;
    padding: 40px 30px;
}

.content-screen p {
    margin: 15px 0;
    font-size: 18px;
    color: #666;
}

.receipt {
    background-color: #f9f9f9;
    border: 1px dashed #ddd;
    border-radius: 8px;
    padding: 20px;
    margin: 25px 0;
    text-align: left;
}

.receipt h3 {
    text-align: center;
    margin-bottom: 15px;
    color: #333;
    font-size: 18px;
}

.receipt-item {
    display: flex;
    justify-content: space-between;
    margin-bottom: 10px;
    font-size: 16px;
    color: #555;
}

.receipt-item.total {
    margin-top: 15px;
    padding-top: 15px;
    border-top: 1px dashed #ddd;
    font-weight: 700;
    font-size: 18px;
    color: #333;
}

.receipt-message {
    text-align: center;
    margin-top: 15px;
    font-style: italic;
    color: #888;
    font-size: 14px;
}

.restart-button {
    margin-top: 20px;
    padding: 12px 25px;
    background-color: #2196F3;
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 16px;
    cursor: pointer;
    transition: background-color 0.2s ease;
}

.restart-button:hover {
    background-color: #1976D2;
}

.share-container {
    margin-top: 25px;
}

.share-text {
    margin-bottom: 15px;
    font-size: 16px;
    color: #666;
}

.share-box {
    display: flex;
    margin: 15px 0;
    width: 100%;
}

#share-text {
    flex-grow: 1;
    padding: 10px 15px;
    border: 2px solid #e0e0e0;
    border-right: none;
    border-radius: 6px 0 0 6px;
    font-size: 14px;
    color: #555;
    background-color: #f9f9f9;
}

#copy-button {
    padding: 10px 20px;
    background-color: #4CAF50;
    color: white;
    border: none;
    border-radius: 0 6px 6px 0;
    font-size: 14px;
    cursor: pointer;
    transition: background-color 0.2s ease;
}

#copy-button:hover {
    background-color: #3e8e41;
}

.copy-message {
    font-size: 14px;
    color: #4CAF50;
    margin-top: 5px;
    transition: opacity 0.3s ease;
}

.copy-message.hidden {
    opacity: 0;
}

.custom-tip-screen {
    text-align: center;
}

.custom-tip-screen h2 {
    margin-bottom: 20px;
    font-size: 20px;
    color: #333;
}

.custom-input {
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 15px;
    position: relative;
    width: 80%;
    margin-left: auto;
    margin-right: auto;
}

.dollar-sign {
    position: absolute;
    left: 15px;
    font-size: 20px;
    color: #666;
}

#custom-amount {
    width: 100%;
    padding: 15px 15px 15px 30px;
    font-size: 20px;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    text-align: center;
}

#custom-amount:focus {
    outline: none;
    border-color: #2196F3;
}

.tip-percentage {
    margin-bottom: 20px;
    font-size: 16px;
    color: #666;
}

.custom-buttons {
    display: flex;
    justify-content: space-between;
    gap: 15px;
}

.cancel-button, .confirm-button {
    flex: 1;
    padding: 12px;
    border-radius: 6px;
    font-size: 16px;
    cursor: pointer;
    transition: all 0.2s ease;
}

.cancel-button {
    background-color: #f8f8f8;
    border: 2px solid #e0e0e0;
    color: #666;
}

.confirm-button {
    background-color: #2196F3;
    border: none;
    color: white;
}

.cancel-button:hover {
    background-color: #f0f0f0;
}

.confirm-button:hover {
    background-color: #1976D2;
}

/* Responsive adjustments */
@media (max-width: 480px) {
    .tip-options {
        grid-template-columns: 1fr;
    }
    
    h1 {
        font-size: 20px;
    }
    
    .subheader {
        font-size: 16px;
    }
    
    .logo {
        font-size: 32px;
    }
    
    .logo.large {
        font-size: 48px;
    }
}