/* --- General Styles --- */
:root {
    --primary-color: #007bff;
    --primary-light: #e6f2ff;
    --secondary-color: #6c757d;
    --background-color: #f8f9fa;
    --card-bg-color: #ffffff;
    --text-color: #333;
    --border-color: #dee2e6;
    --success-color: #28a745;
    --warning-color: #fd7e14;
    --danger-color: #dc3545;
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
}

.grade-calculator-container {
    font-family: var(--font-family);
    background-color: var(--background-color);
    padding: 20px;
    border-radius: 8px;
    max-width: 900px;
    margin: 20px auto;
    color: var(--text-color);
}

/* --- Header --- */
.calculator-header {
    text-align: center;
    margin-bottom: 25px;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 15px;
}
.calculator-header h2 {
    color: var(--primary-color);
    margin: 0 0 5px 0;
}
.calculator-header p {
    color: var(--secondary-color);
    margin: 0;
    font-size: 0.95rem;
}

/* --- Form & Fields --- */
#grade-form fieldset {
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 15px 20px;
    margin-bottom: 20px;
    background-color: var(--card-bg-color);
}
#grade-form legend {
    font-weight: 600;
    padding: 0 10px;
    color: var(--primary-color);
}

.category {
    background: var(--background-color);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 15px;
    margin-bottom: 15px;
    transition: box-shadow 0.2s ease;
}
.category:focus-within {
    box-shadow: 0 0 0 2px var(--primary-light);
}

.category-header {
    display: flex;
    gap: 10px;
    align-items: center;
    margin-bottom: 15px;
}
.category-header .input-group {
    flex-grow: 1;
}

.input-group {
    display: flex;
    flex-direction: column;
}
.input-group label {
    font-size: 0.9rem;
    font-weight: 500;
    margin-bottom: 5px;
    color: var(--secondary-color);
}
.input-group input {
    padding: 8px 10px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 1rem;
    transition: border-color 0.2s ease;
}
.input-group input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px var(--primary-light);
}

.assignments-container {
    margin-left: 10px;
    padding-left: 15px;
    border-left: 2px solid var(--primary-light);
}
.assignment-row {
    display: grid;
    grid-template-columns: 1fr 1fr 40px;
    gap: 10px;
    align-items: center;
    margin-bottom: 10px;
}

.btn {
    padding: 8px 15px;
    border-radius: 5px;
    border: 1px solid transparent;
    cursor: pointer;
    font-size: 0.9rem;
    font-weight: 500;
    display: inline-flex;
    align-items: center;
    gap: 5px;
    transition: all 0.2s ease;
}
.btn-primary {
    background-color: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}
.btn-primary:hover {
    background-color: #0056b3;
}
.btn-secondary {
    background-color: var(--background-color);
    color: var(--text-color);
    border: 1px solid var(--border-color);
}
.btn-secondary:hover {
    background-color: #e2e6ea;
}
.btn-danger {
    background-color: transparent;
    color: var(--danger-color);
    border: none;
    padding: 5px;
}
.btn-danger:hover {
    background-color: #fbebee;
}

.controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 10px;
}
.warning-message {
    color: var(--warning-color);
    font-weight: 500;
    font-size: 0.9rem;
}

.future-planning-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}

/* --- Results Section --- */
.results-section {
    background-color: var(--card-bg-color);
    padding: 20px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
}
.results-section h3 {
    text-align: center;
    margin-top: 0;
    margin-bottom: 20px;
}
.results-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    grid-template-rows: auto;
    gap: 20px;
}
.result-box {
    background-color: var(--background-color);
    padding: 20px;
    border-radius: 6px;
    text-align: center;
}
.result-box h4 {
    margin: 0 0 10px 0;
    color: var(--secondary-color);
    font-weight: 500;
}
.grade-value {
    font-size: 2.5rem;
    font-weight: 700;
    margin: 0 0 10px 0;
}
.primary-result .grade-value { color: var(--primary-color); }
.secondary-result .grade-value { color: var(--success-color); }
.secondary-result span { font-size: 0.85rem; color: var(--secondary-color); }

.progress-bar-container {
    height: 10px;
    width: 100%;
    background-color: #e9ecef;
    border-radius: 5px;
    overflow: hidden;
}
.progress-bar {
    height: 100%;
    width: 0%;
    background-color: var(--primary-color);
    border-radius: 5px;
    transition: width 0.5s ease-in-out;
}

.chart-box, .breakdown-box {
    grid-column: span 2;
}

/* --- Category Chart --- */
.category-chart {
    display: flex;
    justify-content: center;
    align-items: flex-end;
    gap: 5px;
    height: 150px;
    width: 100%;
    padding: 10px 0;
}
.chart-bar {
    flex-grow: 1;
    background-color: var(--primary-color);
    border-radius: 4px 4px 0 0;
    position: relative;
    transition: height 0.3s ease-out;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    align-items: center;
    color: white;
    text-align: center;
}
.chart-bar .bar-label {
    font-size: 0.75rem;
    writing-mode: vertical-rl;
    text-orientation: mixed;
    transform: rotate(180deg);
    padding-bottom: 5px;
    opacity: 0;
    transition: opacity 0.3s;
}
.chart-bar:hover .bar-label { opacity: 1; }
.chart-bar .bar-weight {
    font-size: 0.8rem;
    font-weight: bold;
    padding: 5px 0;
}
.chart-placeholder {
    color: var(--secondary-color);
    align-self: center;
}

/* --- Grade Breakdown --- */
#grade-breakdown-list {
    list-style-type: none;
    padding: 0;
    margin: 0;
    text-align: left;
}
#grade-breakdown-list li {
    padding: 8px 0;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
}
#grade-breakdown-list li:last-child {
    border-bottom: none;
}
#grade-breakdown-list .breakdown-name {
    font-weight: 500;
}
#grade-breakdown-list .breakdown-value {
    font-weight: bold;
    color: var(--primary-color);
}

/* --- Tooltips --- */
.tooltip-trigger {
    display: inline-block;
    cursor: help;
    border: 1px solid var(--secondary-color);
    color: var(--secondary-color);
    width: 16px;
    height: 16px;
    border-radius: 50%;
    text-align: center;
    font-size: 12px;
    line-height: 14px;
    position: relative;
}
.tooltip-trigger::after {
    content: attr(data-tooltip);
    position: absolute;
    bottom: 125%;
    left: 50%;
    transform: translateX(-50%);
    background-color: #333;
    color: white;
    padding: 5px 10px;
    border-radius: 4px;
    font-size: 0.8rem;
    white-space: nowrap;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.2s ease, visibility 0.2s ease;
    z-index: 10;
}
.tooltip-trigger:hover::after {
    opacity: 1;
    visibility: visible;
}

/* --- Responsive Design --- */
@media (max-width: 768px) {
    .calculator-main {
        padding: 0;
    }
    .results-grid {
        grid-template-columns: 1fr;
    }
    .chart-box, .breakdown-box {
        grid-column: auto;
    }
    .future-planning-grid {
        grid-template-columns: 1fr;
    }
    .category-header {
        flex-direction: column;
        align-items: stretch;
    }
    .assignment-row {
        grid-template-columns: 1fr 1fr 30px;
        gap: 5px;
    }
    .btn {
        padding: 10px 12px;
    }
}