:root {
    --primary-color: #3498db;
    --primary-hover: #2980b9;
    --green-color: #2ecc71;
    --yellow-color: #f1c40f;
    --red-color: #e74c3c;
    --light-gray: #f8f9fa;
    --dark-gray: #343a40;
    --border-color: #dee2e6;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.08);
}

body {
    font-family: 'Poppins', sans-serif;
    background-color: var(--light-gray);
    margin: 0;
    padding: 20px;
    color: var(--dark-gray);
}

.container {
    max-width: 700px;
    margin: 0 auto;
    background-color: #fff;
    padding: 25px;
    border-radius: 12px;
    box-shadow: var(--shadow);
}

h1 {
    text-align: center;
    color: var(--dark-gray);
    font-size: 24px;
    margin-bottom: 25px;
}

#client-form {
    display: flex;
    gap: 10px;
    margin-bottom: 25px;
}

#client-name-input {
    flex-grow: 1;
    padding: 10px 12px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 14px;
}
#client-name-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(52, 152, 219, 0.2);
}

#add-client-btn {
    padding: 10px 18px;
    border: none;
    background-color: var(--primary-color);
    color: white;
    border-radius: 8px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    transition: background-color 0.3s;
}

#add-client-btn:hover {
    background-color: var(--primary-hover);
}

#client-list {
    list-style: none;
    padding: 0;
}

.client-item {
    display: flex;
    align-items: center;
    padding: 12px 15px;
    border-bottom: 1px solid var(--border-color);
    transition: background-color 0.2s;
}
.client-item:last-child {
    border-bottom: none;
}
.client-item:hover {
     background-color: #f8f9fa;
}

.client-details {
    flex-grow: 1;
    display: flex;
    align-items: center;
    cursor: pointer;
}

.status-dot {
    width: 15px;
    height: 15px;
    border-radius: 50%;
    margin-right: 15px;
    flex-shrink: 0;
}
.status-green { background-color: var(--green-color); }
.status-yellow { background-color: var(--yellow-color); }
.status-red { background-color: var(--red-color); }

.client-name-display {
    font-size: 16px;
    font-weight: 500;
}

.warning {
    color: var(--red-color);
    font-weight: 600;
    margin-left: 15px;
    font-size: 12px;
}

.check-in-btn {
    padding: 6px 12px;
    border: none;
    background-color: var(--green-color);
    color: white;
    border-radius: 6px;
    cursor: pointer;
    font-weight: 500;
    font-size: 12px;
    transition: background-color 0.3s;
}
.check-in-btn:hover {
    background-color: #27ae60;
}

.modal { display: none; position: fixed; z-index: 1000; left: 0; top: 0; width: 100%; height: 100%; overflow: auto; background-color: rgba(0,0,0,0.5); animation: fadeIn 0.3s; }
.modal-content { background-color: #fefefe; margin: 15% auto; padding: 25px; border: 1px solid #888; width: 90%; max-width: 500px; border-radius: 10px; box-shadow: 0 5px 15px rgba(0,0,0,0.3); animation: slideIn 0.3s; }
.modal-header { display: flex; justify-content: space-between; align-items: center; padding-bottom: 15px; border-bottom: 1px solid var(--border-color); }
#modal-client-name { font-size: 22px; font-weight: 600; }
.close-btn { color: #aaa; font-size: 28px; font-weight: bold; cursor: pointer; }
.close-btn:hover, .close-btn:focus { color: black; }
#checkin-history-list { list-style: none; padding: 0; margin-top: 20px; max-height: 300px; overflow-y: auto; }
#checkin-history-list li { padding: 10px; border-bottom: 1px solid #f0f0f0; }
#checkin-history-list li:last-child { border-bottom: none; }
@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }
@keyframes slideIn { from { transform: translateY(-50px); } to { transform: translateY(0); } }