/* ===== Filter Bar ===== */
.notes-filter-group {
    margin-bottom: 16px;
}

.notes-filter-label {
    display: block;
    font-weight: 600;
    font-size: 13px;
    text-transform: uppercase;
    letter-spacing: 0.8px;
    color: #555;
    margin-bottom: 6px;
}

.notes-select {
    width: 100%;
    padding: 10px 14px;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    font-size: 14px;
    color: #333;
    background: #fff;
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%23555' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 14px center;
    cursor: pointer;
    transition: border-color 0.2s;
}

.notes-select:focus {
    outline: none;
    border-color: #333333;
}

/* ===== Subjects Panel ===== */
.subjects-panel {
    border-radius: 10px;
    overflow: hidden;
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.09);
    background: #fff;
    height: 100%;
}

.subjects-panel-header {
    background: linear-gradient(90deg, #333333, #333333);
    color: #fff;
    padding: 14px 18px;
    font-size: 14px;
    font-weight: 700;
    letter-spacing: 1px;
    text-transform: uppercase;
    display: flex;
    align-items: center;
    gap: 10px;
}

.subjects-list {
    overflow-y: auto;
    max-height: 620px;
    scrollbar-width: thin;
    scrollbar-color: #333333 #eee;
}

.subjects-list::-webkit-scrollbar {
    width: 4px;
}

.subjects-list::-webkit-scrollbar-track {
    background: #eee;
}

.subjects-list::-webkit-scrollbar-thumb {
    background: #333333;
    border-radius: 4px;
}

.subject-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 14px 18px;
    border-bottom: 1px solid #f0f0f0;
    cursor: pointer;
    transition: background 0.15s, border-left 0.15s;
    border-left: 3px solid transparent;
    text-decoration: none;
    color: #333;
}

.subject-item:hover {
    background: #f3f0ff;
    border-left-color: #333333;
    color: #333333;
}

.subject-item.active {
    background: #ede9ff;
    border-left-color: #333333;
    color: #333333;
    font-weight: 600;
}

.subject-item .subject-icon {
    width: 34px;
    height: 34px;
    background: linear-gradient(135deg, #333333, #333333);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.subject-item .subject-icon i {
    color: #fff;
    font-size: 14px;
}

.subject-item .subject-name {
    font-size: 14px;
    line-height: 1.4;
    flex: 1;
}

.subject-item .subject-arrow {
    color: #bbb;
    font-size: 12px;
    flex-shrink: 0;
}

.subject-item.active .subject-arrow {
    color: #333333;
}

/* ===== PDF Panel ===== */
.pdf-panel {
    border-radius: 10px;
    overflow: hidden;
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.09);
    background: #fff;
    min-height: 400px;
}

.pdf-placeholder {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 400px;
    color: #bbb;
    gap: 12px;
}

.pdf-placeholder i {
    font-size: 48px;
    color: #d0c8ff;
}

.pdf-placeholder p {
    font-size: 15px;
    color: #999;
}

.pdf-viewer-header {
    background: linear-gradient(90deg, #333333, #333333);
    color: #fff;
    padding: 14px 18px;
    font-size: 14px;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 10px;
}

/* ===== Empty / Prompt States ===== */
.notes-empty-state {
    text-align: center;
    padding: 60px 20px;
    color: #aaa;
}

.notes-empty-state i {
    font-size: 52px;
    color: #d0c8ff;
    display: block;
    margin-bottom: 16px;
}

.notes-empty-state p {
    font-size: 16px;
    color: #999;
}