/* Import Google Font */
@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@300;400;500;600&display=swap');

/* CSS Variables */
:root {
    --primary-color: #007bff;
    --primary-hover: #0056b3;
    --secondary-color: #6c757d;
    --secondary-hover: #5a6268;
    --success-color: #28a745;
    --success-hover: #218838;
    --danger-color: #dc3545;
    --danger-hover: #c82333;
    --warning-color: #ffc107;
    --warning-hover: #e0a800;
    --info-color: #17a2b8;
    --info-hover: #138496;
    --light-bg: #f8f9fa;
    --white-bg: #ffffff;
    --dark-text: #343a40;
    --medium-text: #495057;
    --light-text: #6c757d;
    --border-color: #dee2e6;
    --border-radius: 8px;
    --box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
    --font-family: 'Poppins', sans-serif;
}

/* General Layout */
body {
    font-family: var(--font-family);
    margin: 0;
    padding: 20px;
    background: linear-gradient(135deg, #e9f1ff, #d6e4ff); /* Slightly adjusted gradient */
    color: var(--dark-text);
    line-height: 1.6;
}

#app {
    max-width: 900px;
    margin: 40px auto;
    padding: 35px;
    background-color: var(--white-bg);
    box-shadow: var(--box-shadow);
    border-radius: var(--border-radius);
    border: 1px solid var(--border-color);
}

h1 {
    text-align: center;
    color: var(--primary-color);
    margin-bottom: 40px;
    font-weight: 600;
}

h2.section-header {
    color: var(--medium-text);
    margin-bottom: 20px;
    border-bottom: 2px solid var(--primary-color);
    padding-bottom: 10px;
    font-weight: 500;
    font-size: 1.4rem;
}

ul {
    list-style-type: none;
    padding: 0;
    margin: 0;
}

/* Section Styling */
.section {
    margin-bottom: 35px;
    padding: 25px;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    background-color: var(--white-bg);
    box-shadow: 0 2px 6px rgba(0,0,0,0.05);
    transition: opacity 0.3s ease-in-out;
}

/* Form Styling */
.form-group {
    margin-bottom: 20px;
    display: flex;
    flex-direction: column;
}

.form-group label {
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--medium-text);
    font-size: 0.95rem;
}

input[type="text"],
input[type="number"],
input[type="date"] {
    width: 100%;
    padding: 12px 15px;
    margin-bottom: 10px;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 1rem;
    box-sizing: border-box;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

input[type="text"]:focus,
input[type="number"]:focus,
input[type="date"]:focus,
select:focus { /* Add select to focus styles */
    border-color: var(--primary-color);
    outline: 0;
    box-shadow: 0 0 0 0.2rem rgba(0, 123, 255, 0.2);
}

/* Style for Select Dropdown */
select {
    width: 100%;
    padding: 12px 15px;
    margin-bottom: 10px;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 1rem;
    box-sizing: border-box;
    background-color: var(--white-bg); /* Ensure background color */
    color: var(--dark-text); /* Ensure text color */
    appearance: none; /* Remove default appearance */
    background-image: url('data:image/svg+xml;charset=US-ASCII,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20width%3D%22292.4%22%20height%3D%22292.4%22%3E%3Cpath%20fill%3D%22%23007bff%22%20d%3D%22M287%2069.4a17.6%2017.6%200%200%200-13-5.4H18.4c-5%200-9.3%201.8-12.9%205.4A17.6%2017.6%200%200%200%200%2082.2c0%205%201.8%209.3%205.4%2012.9l128%20127.9c3.6%203.6%207.8%205.4%2012.8%205.4s9.2-1.8%2012.8-5.4L287%2095c3.5-3.5%205.4-7.8%205.4-12.8%200-5-1.9-9.2-5.5-12.8z%22%2F%3E%3C%2Fsvg%3E'); /* Custom dropdown arrow */
    background-repeat: no-repeat;
    background-position: right 15px center;
    background-size: 10px 10px;
    cursor: pointer;
}

/* Style for Select Dropdown in Edit Mode */
.project-list li select {
     padding: 8px 10px;
     font-size: 0.9rem;
     margin-bottom: 5px;
     width: auto; /* Allow natural width */
     flex-grow: 1; /* Allow select to grow */
     margin-right: 10px; /* Match input spacing */
}

/* Button Styling */
button {
    padding: 10px 20px;
    border: none;
    background-color: var(--primary-color);
    color: var(--white-bg);
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 0.95rem;
    font-weight: 500;
    transition: background-color 0.2s ease, transform 0.1s ease, box-shadow 0.2s ease;
    margin-top: 10px;
    align-self: flex-start;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

button:hover {
    background-color: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.15);
}

button:active {
    transform: translateY(0);
    box-shadow: 0 1px 2px rgba(0,0,0,0.1);
}

button:disabled {
    background-color: var(--secondary-color);
    cursor: not-allowed;
    opacity: 0.65;
    transform: none;
    box-shadow: none;
}

/* Specific Button Styles */
#add-friend, #add-project {
    background-color: var(--success-color);
    padding: 12px 25px;
    font-size: 1rem;
}
#add-friend:hover, #add-project:hover {
    background-color: var(--success-hover);
}

#generate-split {
    background-color: var(--warning-color);
    color: var(--dark-text);
}
#generate-split:hover {
    background-color: var(--warning-hover);
}

#generate-pdf {
    background-color: var(--info-color);
    margin-left: 10px;
}
#generate-pdf:hover {
    background-color: var(--info-hover);
}

/* List Styling */
.friend-list, .project-list, .split-list {
    margin-top: 20px;
    border: 1px solid var(--border-color);
    padding: 20px;
    border-radius: var(--border-radius);
    background-color: var(--light-bg);
    min-height: 60px;
}

.friend-list li, .project-list li, .split-list li {
    background-color: var(--white-bg);
    margin-bottom: 10px;
    padding: 15px 20px;
    border-radius: var(--border-radius);
    display: flex;
    justify-content: space-between;
    align-items: center;
    border: 1px solid #e9ecef;
    box-shadow: 0 1px 3px rgba(0,0,0,0.05);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    flex-wrap: wrap;
}
.friend-list li:hover, .project-list li:hover, .split-list li:hover {
    transform: translateY(-1px);
    box-shadow: 0 3px 6px rgba(0,0,0,0.08);
}


/* Buttons within List Items */
.project-list li button, .friend-list li button {
    padding: 5px 10px;
    font-size: 0.85rem;
    margin: 0 0 0 5px;
    box-shadow: none;
    align-self: center;
}
.project-list li button:hover, .friend-list li button:hover {
    transform: none;
    box-shadow: none;
}

/* Specific buttons in list items */
button.remove-btn { background-color: var(--danger-color); }
button.remove-btn:hover { background-color: var(--danger-hover); }
button.edit-btn { background-color: var(--secondary-color); }
button.edit-btn:hover { background-color: var(--secondary-hover); }
button.save-btn { background-color: var(--success-color); }
button.save-btn:hover { background-color: var(--success-hover); }
button.cancel-btn { background-color: var(--secondary-color); opacity: 0.8; }
button.cancel-btn:hover { background-color: var(--secondary-hover); opacity: 1;}


/* Edit Mode Styling within Project List Item */
.project-list li input[type="text"],
.project-list li input[type="number"] {
    padding: 8px 10px;
    font-size: 0.9rem;
    margin-bottom: 5px;
    width: auto;
    flex-grow: 1;
}
.project-list li input[type="number"] {
    max-width: 100px;
}
.project-list li > div.edit-mode-controls { /* Target specific div for edit controls */
    width: 100%;
    margin-top: 10px;
}
.project-list li > div.edit-mode-friends { /* Target specific div for edit friends */
     width: 100%;
     margin-top: 10px;
     border-top: 1px solid #eee;
     padding-top: 10px;
}


/* === Improved Checkbox Styling ("Split Among") === */
.checkbox-container { /* Generic class for checkbox lists */
    margin-top: 15px;
    padding: 15px;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    background-color: #fdfdff; /* Slightly different background */
    max-height: 200px; /* Increased max height */
    overflow-y: auto;
    display: grid; /* Use grid for columns */
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); /* Responsive columns */
    gap: 10px; /* Gap between grid items */
}

.checkbox-container label {
    display: flex; /* Use flex for alignment */
    align-items: center;
    padding: 10px 12px; /* More padding */
    border-radius: 6px;
    cursor: pointer;
    transition: background-color 0.2s ease, box-shadow 0.2s ease;
    font-size: 0.95rem;
    background-color: var(--white-bg);
    border: 1px solid transparent; /* Placeholder for hover/checked border */
    box-shadow: 0 1px 2px rgba(0,0,0,0.05);
}

.checkbox-container label:hover {
    background-color: #f1f3f5; /* Subtle hover */
    border-color: #ced4da;
}

.checkbox-container input[type="checkbox"] {
    margin-right: 12px;
    cursor: pointer;
    transform: scale(1.1);
    accent-color: var(--primary-color); /* Modern way to color checkboxes */
    flex-shrink: 0; /* Prevent checkbox from shrinking */
}

/* Style label when checkbox is checked (using :has is ideal but not fully supported, fallback needed) */
/* Basic visual cue - might need JS for more complex styling */
.checkbox-container input[type="checkbox"]:checked + span {
     font-weight: 500; /* Make text bold when checked */
     color: var(--primary-color);
}
.checkbox-container label:has(input[type="checkbox"]:checked) { /* If :has is supported */
    background-color: #e7f1ff;
    border-color: var(--primary-color);
}


/* Utility class for hiding */
.hidden {
    display: none;
}

/* Responsive adjustments */
@media (max-width: 768px) {
    #app {
        padding: 20px;
        margin: 20px auto;
    }
    h1 {
        font-size: 1.8rem;
    }
    h2.section-header {
        font-size: 1.2rem;
    }
    button {
        width: 100%;
        text-align: center;
        padding: 12px 15px;
        margin-left: 0;
    }
    .form-group {
        flex-direction: column;
    }
    input[type="text"],
    input[type="number"],
    input[type="date"] {
        width: 100%;
    }
    .friend-list li, .project-list li, .split-list li {
        flex-direction: column;
        align-items: flex-start;
        padding: 10px 15px;
    }
     .friend-list li span, .project-list li span {
        margin-bottom: 8px;
     }
    .friend-list li button, .project-list li button {
        margin-top: 8px;
        align-self: flex-end;
        margin-left: 5px;
        width: auto;
    }
    .project-list li input[type="text"],
    .project-list li input[type="number"] {
        width: 100%;
        max-width: none;
    }
    .checkbox-container {
        grid-template-columns: 1fr; /* Single column on mobile */
    }
}

/* Hidden container for chart canvases */
.chart-container-hidden {
    position: absolute;
    left: -9999px; /* Move off-screen */
    top: -9999px;
    /* Render charts larger for better PDF quality */
    width: 800px; /* Increased width */
    height: 600px; /* Increased height */
    opacity: 0;
    pointer-events: none;
    z-index: -1; /* Ensure it's behind everything */
}