* {
    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;
    color: #333;
}

.container {
    max-width: 400px;
    margin: 0 auto;
    padding: 20px;
    min-height: 100vh;
}

.screen {
    display: none;
}

.screen.active {
    display: block;
}

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

.header h1 {
    font-size: 24px;
    margin-bottom: 10px;
}

.header p {
    opacity: 0.9;
    font-size: 14px;
}

.card {
    background: white;
    border-radius: 15px;
    padding: 20px;
    margin-bottom: 15px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}

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

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

.input {
    width: 100%;
    padding: 12px 15px;
    border: none;
    border-radius: 10px;
    font-size: 16px;
    background: rgba(255,255,255,0.9);
}

.input-group {
    display: flex;
    gap: 10px;
}

.btn-primary {
    width: 100%;
    padding: 15px;
    background: #4CAF50;
    color: white;
    border: none;
    border-radius: 10px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.3s;
}

.btn-primary:hover {
    background: #45a049;
}

.btn-secondary {
    padding: 12px 20px;
    background: #2196F3;
    color: white;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    white-space: nowrap;
}

.participants-list {
    margin-bottom: 10px;
}

.participant-tag {
    display: inline-block;
    background: rgba(255,255,255,0.2);
    color: white;
    padding: 5px 12px;
    border-radius: 20px;
    margin: 5px 5px 5px 0;
    font-size: 14px;
}

.tabs {
    display: flex;
    background: rgba(255,255,255,0.1);
    border-radius: 10px;
    padding: 5px;
    margin-bottom: 20px;
}

.tab-btn {
    flex: 1;
    padding: 10px;
    background: none;
    border: none;
    color: white;
    cursor: pointer;
    border-radius: 8px;
    transition: background 0.3s;
}

.tab-btn.active {
    background: rgba(255,255,255,0.2);
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

.expense-item, .debt-item {
    background: white;
    border-radius: 10px;
    padding: 15px;
    margin-bottom: 10px;
}

.expense-desc {
    font-weight: 600;
    margin-bottom: 5px;
}

.expense-details {
    font-size: 14px;
    color: #666;
}

.debt-amount {
    font-weight: 600;
    color: #e74c3c;
    margin-top: 5px;
}

.checkbox-group {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: 10px;
    color: white;
    font-weight: normal;
}

.trip-summary {
    background: rgba(255,255,255,0.1);
    border-radius: 10px;
    padding: 15px;
    margin-top: 15px;
}

.summary-item {
    display: flex;
    justify-content: space-between;
    color: white;
    margin-bottom: 5px;
}