.sidebar {
    width: var(--sidebar-width);
    background: var(--bg-sidebar);
    border-right: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    overflow: hidden;
    flex-shrink: 0;
}

.sidebar-header {
    padding: 16px;
}

.sidebar-header h1 {
    margin: 0;
    font-size: 20px;
    font-weight: 700;
}

#newChatBtn {
    width: 100%;
    background: var(--accent);
    color: #ffffff;
    border: none;
    padding: 10px;
    border-radius: var(--radius-sm);
    margin-top: 12px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    transition: background 0.15s;
}

#newChatBtn:hover {
    background: var(--accent-hover);
}

.session-list {
    flex: 1;
    overflow-y: auto;
    padding: 8px;
}

.session-item {
    padding: 10px 12px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    text-overflow: ellipsis;
    white-space: nowrap;
    overflow: hidden;
    font-size: 14px;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 8px;
    transition: background 0.1s;
}

.session-item:hover {
    background: var(--border);
}

.session-item.active {
    background: var(--border);
    font-weight: 500;
}

.session-item .session-title {
    flex: 1;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.session-item .session-delete {
    opacity: 0;
    background: none;
    border: none;
    color: var(--text-tertiary);
    cursor: pointer;
    font-size: 16px;
    padding: 2px 4px;
    flex-shrink: 0;
    transition: opacity 0.15s, color 0.15s;
}

.session-item:hover .session-delete {
    opacity: 1;
}

.session-item .session-delete:hover {
    color: var(--danger);
}

.sidebar-footer {
    padding: 12px;
    border-top: 1px solid var(--border);
}

@media (max-width: 768px) {
    .sidebar {
        box-shadow: 2px 0 12px rgba(0, 0, 0, 0.3);
    }
}