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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: #f5f5f5;
    color: #333;
    padding: 0;
    margin: 0;
}

.container {
    max-width: 600px;
    margin: 0 auto;
    padding: 20px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.header {
    text-align: center;
    margin-bottom: 24px;
}

.header h1 {
    font-size: 24px;
    font-weight: 600;
    color: #1a1a1a;
}

.people-list {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-bottom: 20px;
}

.person-card {
    background: white;
    border-radius: 12px;
    padding: 16px 20px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.person-card:active {
    transform: scale(0.98);
    box-shadow: 0 1px 4px rgba(0, 0, 0, 0.1);
}

.person-name {
    font-size: 18px;
    font-weight: 500;
    color: #1a1a1a;
}

.person-balance {
    font-size: 18px;
    font-weight: 600;
    color: #2ecc71;
}

.person-balance.low {
    color: #e74c3c;
}

.add-btn {
    background: #007aff;
    color: white;
    border: none;
    border-radius: 12px;
    padding: 16px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s;
    width: 100%;
}

.add-btn:active {
    background: #0051d5;
}

.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    z-index: 1000;
    align-items: center;
    justify-content: center;
}

.modal.active {
    display: flex;
}

.modal-content {
    background: white;
    border-radius: 16px;
    padding: 24px;
    width: 90%;
    max-width: 400px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
}

.modal-content h2 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 16px;
    color: #1a1a1a;
}

.modal-content input {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    font-size: 16px;
    margin-bottom: 16px;
    outline: none;
    transition: border-color 0.2s;
}

.modal-content input:focus {
    border-color: #007aff;
}

.modal-buttons {
    display: flex;
    gap: 12px;
}

.modal-buttons button {
    flex: 1;
    padding: 12px;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: opacity 0.2s;
}

.btn-primary {
    background: #007aff;
    color: white;
}

.btn-primary:active {
    opacity: 0.8;
}

.btn-secondary {
    background: #e0e0e0;
    color: #333;
}

.btn-secondary:active {
    opacity: 0.8;
}

.empty-state {
    text-align: center;
    padding: 40px 20px;
    color: #999;
    font-size: 16px;
}