/* ==================================================
   Sidebar Structure
   ================================================== */
.sidebar-desktop {
    width: 250px;
    position: fixed;
    height: 100vh;
    top: 0;
    left: 0;
    z-index: 1020;
    transition: all 0.3s ease;
    overflow-x: hidden;
    white-space: nowrap;
    background-color: #212529;
    box-shadow: 2px 0 8px rgba(0,0,0,0.15);
}

.sidebar-desktop.collapsed {
    width: 70px;
}

/* ==================================================
   Wrapper (Content shift)
   ================================================== */
#wrapper {
    width: auto;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    transition: margin-left 0.3s ease;
    margin-left: 0;
}

/* Desktop: มี sidebar (admin/manager/public) */
@media (min-width: 992px) {
    body:not(.hide-sidebar) #wrapper {
        margin-left: 250px;
    }
    body:not(.hide-sidebar) #wrapper.expanded {
        margin-left: 70px;
    }
}

/* Student: ไม่มี sidebar */
body.hide-sidebar #wrapper {
    margin-left: 0 !important;
}

body.hide-sidebar .sidebar-desktop {
    display: none !important;
}

/* ==================================================
   Sidebar Links
   ================================================== */
.sidebar-link {
    position: relative;
    color: #dee2e6;
    padding: 0.6rem 1rem;
    border-radius: 0;
    transition: background-color 0.2s ease, color 0.2s ease;
}

.sidebar-link:hover {
    background-color: rgba(255,255,255,0.08);
    color: #ffffff;
}

.sidebar-link.active,
.active-reg {
    background-color: rgba(255,255,255,0.12);
    color: #ffffff !important;
    font-weight: 600;
}

.sidebar-link.active::before,
.active-reg::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    width: 4px;
    height: 100%;
    background-color: #ffc107;
}

/* ==================================================
   Sidebar Section Header
   ================================================== */
.sidebar-link-header {
    background-color: #343a40;
    color: #adb5bd;
    font-size: 0.75rem;
    letter-spacing: 0.5px;
    text-transform: uppercase;
    padding: 0.5rem 1rem;
    border: none;
}

/* ==================================================
   Collapsed Mode
   ================================================== */
.sidebar-desktop.collapsed .link-text,
.sidebar-desktop.collapsed .sidebar-link-header {
    display: none;
}

.sidebar-desktop.collapsed .list-group-item {
    text-align: center;
    padding-left: 0;
    padding-right: 0;
    display: flex;
    justify-content: center;
}